Steven, I have a 32 year old son who also wants a wife. He is one of the finest men I know, actually (no prejudice here...LOL). Several years ago he was totally in love with a young woman but some of those 'red flags' kept appearing and she ended up deciding she did not want to be serious with him and she broke up with him. He was really brokenhearted at the time. He looks back now and thanks God they did not end up together as he has seen what has happened to her since.
Be content in the situation God has put you in. You are single right now. There is a reason for that. When YOU are ready to be married (despite how you may currently feel about yourself, God knows better), then the right girl will come along.
Do NOT marry a Mormon. Even if she were to convert, the pull from her family to go back or be disinherited by them would tear her, and most likely your marriage, apart. You cannot rescue her. If she, at some point in her life, decides to follow the truth about Jesus and convert to true Christianity, God will have the people around her to help support and sustain her through an incredibly difficult time. I don't think you have any idea of the hold the LDS church has on its members and their families.
You do not want to get involved. Be friends. Talk to her about the Jesus of the Bible. But stay WELL away emotionally. You have no idea of the pain you will find yourself immersed in if you get involved.
Paul warns us most strongly against light having anything to do in partnership with darkness. Believe him.