What do I do about him?

Okay so Im a senior and Im going to summer school to get ahead in my class, and there is this boy who's extremely Christian. I'm not religious in any way but he keeps harassing me about the subject. He is a sweet, sweet boy and just looooves his religion and government. Everyday he tries getting me into his religion and I don't believe in it. I cant be mean to him, because he helps me all the time in class and and is just so nice. (He kills me with kindness!) I guess if I were to start being christian again it would be alright... but I don't want to be a hypocrite because I've always said I'm not a god believer and that I've lost all my faith. I don't feel that there is a god, and how am I supposed to believe in it if I don't feel he's there? I love listening to him talk about his religion because his heart is so into it, but how do I turn him away without hurting him?