DO NOT just come out and tell her you have such deep feelings for her, she will walk all over you, they see this as weakness for some reason, especially the hot ones, and if she had a bf and she continues to flirt with you think what she will do when (if) you date her, i know so many girls who are total flirts, i have friends that are girls who have kissed me infront of thier boyfriends, i dont know about most guys but that would not sit well with me if i was the bf, bottom line, shes probably not worth the heart ache and embarassment, so either ask her out, or move on