one more thought about why the trust factor might be a little easier with professional ladies;
one of the dommes i played with was, by far, my favorite...i was a little enamored of her...unfortunately, she seems to have left town, if not the business. anyways, this lady was hot, creative, challenging, technically skilled with bondage and toys, alert to limits, and a complete natural with the verbal element of the sessions. the client hired her several times, which was great for me
the last time i saw her, we took a cab together after the session, and i asked her how she got into the business. i was very surprised when she explained that she wasn't dominant at all - a friend of hers was in the business and had encouraged her to come in for some extra income. for her, as a pro domme, the sessions were a theater - a vivid theater - to please the client. (she was very dominant with him, too, which was cute for me to see!)
my point is that - unlike the little evil person in me - a professional is probably not looking to make you uncomfortable. she is probably aiming to please you with the level of pain (if any) you desire, and will be alert to your responses as activities unfold. and, of course, she will play with a safeword. there is plenty of good information out there, in reviews and word of mouth, about who does all this well...and who doesn't. all told, for anyone who wants to experiment with this stuff, i think it's a pretty safe activity.
i do have to say...being a dominatrix looks like exhausting work, both physically and mentally. i couldn't do it - at least not well!