It wasn't a criminal trial. She would have likely won either way, out of court settlement or being awarded compensation by the court.
But thats the argument isnt it, for every point made to why would he settle, theres an equal counterpoint of if she was so likely to have won , why would she settle and not put a high ranking royal through a court trial to a defeat. Like I say, the bottom line is, now we will never know the actual truth. She could have gone on to win a trial, as it was so likely a win, instead by taking an out of court settlement all she has done is open herself to allegations of just wanting a payday (whether thats the truth or not). I cant really see how thats a better path for her than winning the court battle if the evidence was so strong.