How are you acting around him? Have you turned him down? If your acting too hard to get he may have lost interest or simply found some one else. But in contrast he could be playing hard to get himself and failing miserably.
if you are sure she likes you, shes probably ignoring you because she is nervous or playing hard to get.
If he has suddenly started ignoring you, and finding some reason to leave the room as soon as you enter, then that's when a boy is fed up.
If a boy messaged you that he fancies you, that means he likes you or has a crush on you.
make him interested in you
Slap him
yes she is a boy in her class called Matthew fancies her
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.
What it means is the boy doesnt quite like you but he has a thing for you
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.
Ask him.
Ask him out before the other girl.