did you try to make anything happen, or did you try to wait for her to make something happen?, did you go for a kiss?, anything?
or just try to get her to admit it was ok for you to do something?
stop trying to get approval from the girls you like, just take a risk and go for what you want, believe in yourself
but as for this specific girl, you fucked yourself in the ass, you have to move onto other girls now, this one is ''friends'' with you, aka she doesn't want to sleep with you
make your intentions more clear faster, flirt, touch, kiss, get them alone
if those things can not be accomplished, then find a different girl and try again, don't try to logically find out how a girl feels or convince her to like you, or anything like that, don't set anything in stone, just hit on her and see how far you can take it, your actions, and her actions will speak volumes above words, and be realistic with yourself, if a girl doesn't like you, she doesn't like you, no amount of game or lines will change this
she would have to see you as a different person (chances are both physically and emotionally)