Do you have girl friends before? if the answer is yes, u should know how to do in this situation. if the girl and her boy friend's relationship is not good, u should tell the girl to break up with her boy friend. If this is the first time that u 'date' with her, u shouldnt just tell her u love her and u want her to be your girl friend so quickly, if u do this, u will scare her! So, the thing u need to do now is to slower down the speed, try to make friends with her first, and when u think its the time, u need to make something romantic and makes her feel u love her!