The most usual method for finding out whether someone is attracted to you is to flirt with them and see their response. You indicate your interest in a way that they won't feel uncomfortable rejecting you and that you can laugh off as harmless if you are rejected.
For example, you have met someone new and after spending time with them have found that you are attracted to them and would like to make the relationship physical. A heartfelt compliment, an appropriate touch on the hair, face, or arms, or even a soulful look can effectively communicate your romantic feelings.
You have probably seen examples of this in a hundred movies.
Alternatively, you can ask the person directly, but the great thing about doing it with flirtation is that you can choose how much to flirt or how little to flirt based on your impression of how much they are into you at the time.
iam in love with this guy but i do not know if he likes me or some other girl
If a guy likes you but you don't know him he may look at you or walk by you whenever possible.
when he says he likes you.
http://www.wikihow.com/Know-if-a-Guy-Likes-You
Not sure how you expect someone to magically know something.
It is ok to like a guy after you know he likes you. That is perfectly normal and a part of life.
You ask the guy.
don't
Maybe her X, or a guy who likes her but she doesnt like him so hes keeping her captive
his eyes will open wider if he likes it
When he has a penis.
You will know if a guy likes you because he will ask you alot of questions and he will try to get to know you better,but don't think that just because he talks to you that he likes you,make sure that they are the right person!!!