Thomas has it right. The thing is about dating, is the purpose of dating is to meet a mate. So if there is no common foundation, like both being Christians, you are on the wrong foot from square one.
And woe betide should you actually fall in love with an unbeliever. I have a friend who got saved after she was married. She did nothing wrong there. But her husband is still not saved. She has prayed and prayed, and so have her daughters. She loves him and they have a good marriage, but it is not really complete, because she is watching him standing on the abyss, ready to walk into hell if he should suddenly die.
That alone is enough to break her heart. And if you find someone that actually becomes hostile to your faith, you are chancing walking away from God, to please this man.
Please do not date unbelievers ever! Better to remain single than to marry a man who does not know and serve Christ.