I think trust is easier in a pro setting. It's far easier to research and vet a pro Domme than a potential private play partner.. Things like her reputation, the quality of her website, online reviews, posts on forums like this all help in forming an opinion. Of course, the more established the Domme is the easier that is. I've always tended to play with Dommes who are long established and well known.

I think the far greater leap of faith is on the part of a Domme seeing a sub for the first time.