I agree with you about the trust part, trust in people has nothing to do with it.

However, I will say that I know of an evangelist to the native community that said that in many cases, you can't even say anything about the Gospel, until they see you are willing to help them. For instance, he was able to present the Gospel when he actually helped first nation’s people in things like mending nets, loading/unloading fishing boats and other things of that nature.
I have witnessed first hand how he has gained a lot of respect from the First Nations community up and down the coast of British Columbia.
I consider it an honor to be considered a friend of his.

Tom