I agree with MidwestDad3 in that I think OCD should be ruled out. If the OP’s daughter suffers from OCD related scrupulosity, she may worry obsessively that she doesn’t believe in God, that she is gay or transgender, or any number of things that she fears would damn her to hell, without any of those things being the case. This would be different from actually discovering that she doesn’t believe in God, or that she is gay or transgender, and would require a different kind of support.