how do you know if a girl likes you?

Answer 1

Ask her out on a date.
If she says yes, she likes you.
If she says no, she does not like you.
If she starts laughing, she does not like you, but has a good reason.

Answer 2

if shes in your bed naked then definitly.
if she will talk to that is a start. if she is always smiling at you while your talking I would almost say for sure.
the best way to find out for sure!
tell her "I like you and I hope you like me back"

Answer 3

through a smile towards you that takes you awaya from this world.a smile is a mirror of inner heart.