It means that they are only playing you. They are only taking advantage of you liking them.
He likes you back!! He knows and if he flirts he is head over heels for you!!
it means that she knows you like/are in love with her
It sort of tells the girl that you like her back.
She does not like him
It means he likes you back, or he knows you like him, so he tells his friend.
That she probably doesn't like you back.
it definintly does
it means he trusts you he might like you
It could mean the girl finds him to be caring, and could even like him.
that mean they don't like him
Most likely, no. Just because YOU like him, doesn't mean he has to like you back. He told you he didn't like you. He knows that you like him, and if he did like you back, he would've asked you out by now.
It probably means that she would like to kiss you.