How to tell her I like her?

I know this girl I think she sees us at the beginning of a friendship, but I want more. She is preaching to me about christianity and I am asking about it. How do I break the news to her that I want to try and be more than friends with her. She is a very attractive woman and before she gave her life to god she was promiscuous, although I am only 19, I am looking for a lot more than that. How can I make her understand that?