I luv my gulfrnd very much . and even now also she love me . but i only dont noo the reason of our breakup.?

whenever i try to ask her whats the reason of breakup she never answer me . and she was in my area and now she changed the area and whenever i want to talk i catch her in the road and talk with her . whenever i try to talk wiht her she always say "please let me go " not even say i want to breakup. i even ask to tie rakhi . she was like noo... . and even its very hard to catch her in a road near her school because she have a small brother . he will tell to her mother.. i am in big trouble . you galz and guyz please help me....... .. and let me clear you that when my girlfriend mother know about our affairs then my girlfriend start doin all this thing . please say how should i say to my girlfriend that how much i love her . and how to impress her . and she is not bad girl she is a studious girl .