My girl cant reach an orgasim...what is the cause of this ? is it her body?

hi....ive been havin sex with my girl for months now and she tells me that she has never had an orgasim yet and never has reached her pion...ive had sex with her many timw and she has also tryed many things...but for some reason seh could never get that far....what is the reason for this ? and how could i finally make her ***?