If you can't do that, realizing that your partner may never come around to your side of things, you are not ready to marry this person.
We have been married 2 years and datinv a 4 month old baby. If He can answer prayers to help you find missing car keys, He surely can help you understand who it is that you should marry.
If you go yourself, you'll see - those people are good people.
Plan on her family trying to torpedo your relationship if you don't convert.