If a girl isn't sure she likes you, then just be her friend. If you give her space, she'll respect you for that. Don't try to be more than her friend thouggh. That annoys us girls.
When he is sure he likes her.
ask her directly
they way they act around you
Answer Why not ask her then you will know for sure.
Ask her, or a friend of hers.
You can start hanging with the decent girl to try to get close to her bestfriend.
I think that the best thing to do is to tell him. Sure, he doesn't like you, but he deserves to know how you feel
If A girl likes you, she will blush, and stare at you a lot. She will sometimes avoid you too. To improve, a girl will also play fight or bee mean but if she smiles or laughs when she does it she likes u
You go for it, and take her in a alleyway
see if she acts weard and mean to you
Just ask, what is so complicated?
If she likes you then you will most likely get dragged into a corner and snogged until your dead