how about "he has reasons to trust her"?
why is it «til å tro» instead of just «å tro»?
Why reason comes without preposition
Do you mean an article?
I would also accept "He has reason to have faith in her."
"To have faith in someone" means to believe that they will succeed or follow through with something.
"To believe someone" means to believe what they have to say or write.
How would you translate "He has reason to have faith in her." to Norwegian?
My translation would probably be something like:
"Han har grunn til å ha god tro på henne."