First things first. You say you started this relationship with this guy with fornication involved. The fact that you started with that completely nullifies your "evangelism" to this guy. He may be reading his bible but the fact is is that you without words told him its ok to be a hypocrite. Thats what you were preaching to him. My first question is, are you still sleeping with him? (and that includes intercourse, outercourse, heavy petting/intimate touching,oral sex, mutual masturbation etc its all sexual sin). If you were to leave the relationship would he carry on continuing being a "Christian" ? Probably not. And if he can't carry on without you then Jesus is in fact not his saviour but the relationship is and that is a sin and you are causing him to sin (since you are apparently the more "mature" Christian you would be doubly held accountable before the Lord for your actions).
As for him being a genuine Christian there are a couple of things that would stick out in my mind:
- Has he publically made a declaration of faith among the church community or to a mature Christian other than you like the Pastor or someone in leadership?
- If he beleives in Christ then ask him to give his testimony. If he never mentions a personal relationship with Jesus or progress he is making in that then no I wouldn't say he has a genuine faith. The bible says even Satan and demons believe in God and they shudder. So its not enough to say "I believe in God"
- If he has had a genuine faith conversion like above then you should be seeing this in action. Has he joined a church? Immature new christians esp men from other cultures and religions esp have a huge need to join a church and be under discipling mentorship of a trusted male Christian, who should be teaching him how to biblically date and pursue marriage. This cannot come from you!. There are certain things that men need to learn from other men, they cannot learn it from women. Also, have you seen him pray? Whats his prayer life like? No praying= alarm bells.
- Another thing, if he is wanting to be genuinely biblical in his approach has he sought the approval of your family particularly your father? You said you come from a born again christian family. I will take as meaning your parents are christian and they raised you "christianese." If he hasn't bothered or has failed to prove to your family his worth as a potential spouse then no Id say hes failed. Dating is when men (and women) are supposed to be on their best behaviour. If they're not giving you their best during that stage you can be sure as heck you won't get it in marriage.
- Are you wanting to marry this guy just cos you're so prematurely emotionally involved with him? Sounds to be like you're just so incrediably lustful after this guy. And you're pulling the number one dumb mistake that all immature christian women pull. They date and marry spiritually immature men not because its honoring God but because they see "potential." Dumb idea alert!! This man is supposed to lead your family spiritually. You according to the bible are going to have to trust that he is going to base all his decisions on the bible because biblically you will be submitting to him. You are going to be submitting to him negatively or positively. Do you 100% trust that he will do this? And in order for him to do this effectively and take this role seriously has he thoroughly studied the bible and read up on what God expects of him as a man let alone a husband and father?
- Im sure this guy is absolutely lover-ly! But being wonderful and attractive is not enough. Christian divorce is just as high as secular divorce. Oh and heres another thing. Have you even taken into consideration the cultural differences? Have you asked him what role he expects of you to fulfill in marriage? You say hes raised Hindu, does that mean hes Indian or something similar ethnically? Have you looked at his family and esp his mother? Cos I bet you 100 bucks, what hes witnessed of his mother throughout his life I bet he will expect from you. Hindu families are extremely conservative and religious. If he is a so called Christian, what does his family think of this? Does his family still have household idols that they worship? Theres something to think about. Is he still involved in family cultural practices that are just thinly veiled superstitions?
Heres a book I very much recommend -
101 Questions to ask before getting engaged. I recommend you buy it. Its very good.