I think we should not equate our way of making an infinitive. Here is what I mean...
Å tro = to believe
I want to believe Jeg vil tro (not å tro)
Jeg har grunn til å tro henne I have reason to believe her (not to to believe)
I have no clue about the linguistics here. I imagine motion..i.e., belief is something you convey on someone according to how I think.