Almost every pastor I know has run into a painful issue: the daughter of some important figure in the church (perhaps a board member) sets up an appointment with her husband-to-be and asks if the pastor will officiate. The young man, however, does not profess to be a committed believer in Jesus.
From there, paths diverge and all kinds of things can happen. Some churches/pastors have a written policy that at least protects those individual from feeling targeted, if nothing else.
What about your church or yourself (If you are a pastor)? Do you simply say, "The Bible says...." or do you also have a policy that interprets the text in black and white terms.
Discussion might include exemptions (for example, a woman gets saved, has been living with a man for years and has several children with him, she is willing to get married to make things right and so is he, but he is not a believer and not wanting to become one; do you suggest they marry in court, not get married, etc.).