Sometimes the emails have come from the Christian involved in the relationship, but other times from the non-Christian.
I have posted a few of these on the Web site (see Ethics, Spirituality, and Christian Life: Dating).
But I address all of these issues in my book and in various articles on the Web site.
So the first thing I do is to encourage both parties to better understand their own and the other person's faith.
I could post many more, but some contain too personal of information for public posting.
But given the number of emails I have received with these scenarios, this is obviously a pressing issue for many people.
In the case of Mormonism, I have articles posted on the Web site that detail the official teachings of this religion, documented by direct quotations from its "prophets and apostles." See Mormonism for a list of these articles.
Most people are rather shocked to find out what Mormonism really teaches.