they might act nervous around the girl, not being there usual self, being quieter than normal, wanting to hug the girl alot, contacting them alot by text, facebook, phone etc or the obvious of asking them to spend tme with them just the two of them.
If a boy messaged you that he fancies you, that means he likes you or has a crush on you.
Ask him out before the other girl.
If you wana know if he loves you so its in his kiss...thats where it is
if he likes you you should find him staring at you with a look of admiaration.
It means he like you and would like to get to know you better.
Some do, some don't.
You would be super nice to this girl. You should also ask her out or have a friend ask her for you. I am a girl so i would definitely know that girls like it when this happens!
Ask him.
I'd say move on to another boy. Judging by what you provided in your Q, this boy wants to play and have his fun. Don't waste your time.
Kiss him violently in front of the girl he fancies :P
If a shy boy does like you he will become even more shy around you. He will avoid you and try to act cool.
Yes. She is thinking about how great sex would be most likely. I know from experience.