Have you ever been having a nice time with a longtime friend of yours and he suddenly comes out of nowhere with an "I love you"?

You were having fun, laughing at a horrible joke one of you made, and then all of a sudden he gets serious and lays his heart out for you.

You didn't have a clue how he felt, and now you're wondering how you could've missed the signs.

Well, you aren't alone. Many women have been oblivious to men who have strong feelings for them.

To be fair, sometimes when guys fall in love, they make it a bit hard to read them. However, if you pay close attention to his actions, you could've probably guessed he was crushing on you.

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So, keep an eye out around guys who do things like these, because they may actually be signs he loves you.

21 undeniable signs he has strong feelings for you.

1. It always seems like he has something more he wishes he could say.

More often than not, guys know they want to tell you how they feel but they often worry that they can’t.

Whether it’s because you’re dating his friend or because he’s just terrified of admitting feelings, it’s shocking how many guys out there will just bottle it up because they feel like they just can’t say something.

If your gut says he wants to say more, chances are, he does.

2. He seems like he’s scared to tell you his true feelings about random subjects.

You’d be surprised at how many guys will also turn into total doormats around girls they like.

If he regularly rolls over or backpedals, he’s way more into you than he lets on, because your opinion of him means everything and he doesn't want to risk ruining it.

3. He seems open to talking to you about almost anything.

Unlike other people, he feels totally comfortable being super silly, vulnerable and his real, authentic self around you.

He tells you about his past, shares deep, personal stories and feelings, and opens up to you as a romantic partner would to their counterpart.

4. He makes it a point to be super chivalrous.

When a guy goes out of his way to treat you delicately, it’s usually for a particular reason.

If he regularly buys you drinks but doesn’t do the same for other girls, he might see you as more than just a friend.

RELATED: 5 Confusing Things Guys Do That Mean They Like You

5. He distances himself from other girls in your presence.

Guys will often make a point of showing who they want to be with, even if girls are already all over them.

6. When you talk on the phone, there’s lots of awkward pauses.

This goes hand in hand with the whole “wanting to say more” thing. When a guy is interested in you but feels like he has no chance, he often won’t know what to say. Ergo, he’ll start having awkward pauses.

7. He goes full-on Papa Bear on you.

If a guy is into you, there’s a very high chance that he’ll get protective or even a bit possessive of you. If you notice that he regularly gets macho around other guys, he might end up confessing his feelings for you.

8. He appears particularly hurt if you go on an anti-men rant around him.

I will admit I’m very guilty of this one, mainly because I’m so badly burnt by dating men. And my rants are known for being scathing.

I know for a fact most guys will wither a bit hearing my honest-to-god opinion of their gender’s dating habits, but with my close friend, he would legitimately tear up. The reason is that hearing my rants often made him feel inadequate, too.

RELATED: 11 Sure Signs He Loves You And You're Meant To Be Together

9. You get the feeling he’s trying to impress you.

If someone has a crush on you, they will try to flaunt themselves around you.

10. Mutual friends mention that you two would be cute together.

When this happened with me and my close friend, I was pretty oblivious to the fact that my close friend probably asked female friends for help. But, yes, if other female friends of his gently nudge you towards him, he may be really into you.

11. When the two of you are alone, he's clearly nervous.

Body language is a great indicator of nerves. Whether turning beet red and choking on words, avoiding eye contact and squirming, or just having verbal diarrhea, most of the time, girls will know when guys are nervous around them.

Guys don’t get nervous from people they see as “just friends,” capiche?

12. He talks about you to other people in his life.

If his friends and family already knew about you before you met them, that's a sign that he was excited for you to meet them, meaning he's excited about you being a part of his life.

If meeting the people in his life goes smoothly (like they already know you), he's got a thing for you.

You're on his mind and, not only is he unafraid of making you a part of the rest of his life, he's already making that a reality.

RELATED: 11 Things Guys Say Or Text When They Really Like You

13. He smiles a lot around you.

If he has strong feelings for you, you'll probably catch him constantly smiling around you. If you notice that he is almost always happy when you are around him, especially if you seem to be the common denominator, you're probably the reason why.

Take note of how he might even be smiling as if he were holding a secret, or maybe he's always beaming around you, or some combination of the two. Either way, this is a good clue he's into you, especially if he doesn't usually exhibit this behavior around others.

14. He naturally — and frequently — flirts with you.

If a guy is into you and has caught major feelings, his flirting will flow more naturally instead of feeling forced, because he pays attention to what you like and what rubs you the wrong way. The key word here is "pays attention." A guy doesn't pay attention for no reason (just saying).

Beware of this sign though because some guys are just natural flirts; it's their personality.

15. He remembers the little things.

If a guy has feelings for you, he'll make mental notes of your usual coffee order and your favorite musicians, or why you have a scar on your left knee.

He'll remember that you don't like the color yellow because it reminds you of your great Aunt Bertha who wore sickly yellow glasses that freaked you out when you were five. (Cringe.) He cares about you and pays attention to everything you have to say, and he's interested in who you are.

16. Your opinion matters and he respects you.

He cares about your opinion, whether it's about him or about the new ice cream flavor at Baskin Robbins.

Whatever it is, your opinion is a top priority to him and he will listen to what you have to say. He will also respect your thoughts and boundaries.

RELATED: Why Mutual Respect Is So Important In Relationships — And What It Really Means To Be Respectful

17. He uses social media to stay in contact with you.

If a guy is into you social media may be able to tell you before he does. If he isn't spending time with you, he'll be on your social media. He'll be super active and engaging by liking every post and commenting cheeky remarks.

If he's always the first one to like your picture on Instagram, dude's got it bad for you. And he isn't afraid to shout it from the mountain tops. (Or, in this case, one post to another.)

18. He doesn't like when you talk about other guys.

If you start praising another man and laying it on thick as you go on — and on — about how talented the other guy is at something or how he did something to impress you personally, you may catch the eyes of the man in front of you turning green with envy.

He might try to change the subject or bring up something he did that's related to shade or one-up whoever you're talking about in the hopes that this will level what he feels is his competition.

19. He points out your similarities, hobbies and any interests you share.

He wants to demonstrate how much you have in common to establish how compatible the two of you are.

This also opens the door for him to try to spend more time with you without too obviously asking you out because it's not as much of a stretch to suggest that you simply enjoy your favorite activities together as it is for him to completely put himself out there and formally ask you out to dinner.

20. He often compliments you.

If he makes a point of telling you how nice you look, how much he likes a certain dress on you, that he likes your new haircut (read: guys never notice when you get a haircut unless they're really paying serious attention!), then he may only have eyes for you.

This demonstrates how clearly he admires the way you look and that he wants you to know that.

21. He finds excuses to spend time with you.

It doesn't matter what you're doing, he tries to find reasons to do things together or fit into your schedule somehow. And when you're around other people, he'll try to find ways to be close to you, either by sitting next to you or across from you (especially so he can sneak some longing gazes at you!).

Either way, he just likes to be around you — even if you're not doing anything at all.

Guys can be frustratingly — and seemingly endlessly — confusing, at times.

It turns out they aren't always that complicated, though. At least, a good percentage of them. There are always exceptions though, and guys who may drop tons of hints that they like you, only for you to find out that they were just stringing you along.

Not to mention, it can be really tough to tell with guys when they won't just come outright and ask you to dinner or give some other clear, obvious indicator of his interest, or lack thereof.

Ultimately, the only way you can know for sure? It all comes down to one thing: going straight to the source to find out directly how he really feels. No more asking yourself, "Yes or no, does he have feelings for me?" Just ask.

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Ossiana Tepfenhart is a writer based out of Red Bank, New Jersey. She writes primarily about lifestyle, food, finance, and relationships.