We have all heard this before:
I know they will be converted. God can call them if he will; if i just love them and share God with them we can marry and he or she will become a believer later.
Listen to Richard Baxter’s response over 300 years ago,
“First, then, it seems because you love an ungodly person, you will be easily turned to be ungodly. If so, you are not much better already. If love will not draw you to their mind to be ungodly, why should you thing love will draw them to your mind to be godly? Are you stronger in grace than they are in sin? Second, if you know well what grace is and what a sinful, unrenewed soul is, you would not think it so easy a matter to convert a soul. Why are so few converted if it is so easy a thing? You cannot make yourselves better by adding higher degrees to the grace you have; much less can you make others better by giving them the grace that they do not have. Third, it is true that God is able to convert them when he will; and it is true that for aught I know it may be done. What of it? Will you, in so weighty a case, take up with a mere possibility? God can make a beggar rich, and for aught you know the contrary, he will do it; and yet you will not, therefore, marry a beggar; nor will you marry a leper because God can heal him. Why then should you marry an ungodly person because God can convert him? See it done first, if you love your peace and safety.” p44-45