Basically, she believe in that there is one God only. However, she doesnt follow any single scriptures. The quran said marry people who believe ie. people of the book and do not marry disbelievers or people who associate with God. She is in the middle. She has the most important thing which is the belief in God. Is that not the minimum necessary or does she have to follow one the scriptures? She agrees with a lot of the religions but she still isnt convinced by all of it? is it enough that she believes to marry her??