As I recall, you raised this with her and she said you didn't have to agree with her on every detail in order to make progress.

Have you told her you have trouble believing this?

C.S. Lewis addresses this in one of his tracts.

As I understand it:
1. Truth is absolute.
2. Faith means holding to the truth.

His position is that we know the Bible is true because we have proved it. And having proved it, the only sane response is to keep on believing it.

There is nothing mystical about his faith. It's cold, hard logic.