edward said he needed "a professional" with no romantic hassles??

The script of this movie lacks not only a moral compass about prostitution, but any clue to the terrible realities that most prostitutes face. It was originally envisioned as a dark and serious look at these truly hazardous conditions. Apparently, Jeff Katzenberg didn't think that concept would make for a box office hit, and ordered the changes that made it into what it became - a monstrous lie masquerading as a romantic comedy:
https://en.wikipedia.org/wiki/Pretty_Woman#Development

Any lie will find believers as long as you tell it with enough force.

it seems rather unlikely. She doesn't know anything abour edward's world or how to behave in it. if he wanted a professional he could easily have hired an upmarket courtesan who would know all the right things to do and say in his social circle.