I'm writing a character description, and the person I'm describing looks and/or feels like someone you can trust, like someone who would be honest with you, someone innocent, maybe even pure. Even if you just met them. You just have the feeling like anything they say or do is with honest and good intentions and in case something they said or did come out as a lie, as something wrong you still feel the same somehow. It would take something big to change your mind or else you would just think that they didn't mean it like that.
And it doesn't matter if the really didn't mean it or not. I do not mean someone who pretends to be trustable, in this case you don't know if they are what they seem to be or not. So please keep that in mind.
I knew a word, description, idiom or synonym that just fit, but I can't seem to remember. Please help?