People like the Prince, King to be, of one of the most powerful nations of the 19th and 20th century, write their own history. He has teams of clever public relations spinners and whizzers at his disposal. Layers of handlers to keep his hands spotless combined with the power to destroy anyone in the gov't who so much as speculates about it. How could one person without 24-7 teams of highly trained security be any problem for someone like that?
People who have everything are just as capable of murder as someone who has nothing. What makes it difficult to imagine he wanted her dead for the same good old fashioned reasons?
5. Fear (of something becoming known)
I could go on.. Ultimately we really don't and never will know. He's got people and he's a great actor.
Please go on. I'd like you to explain how you know Princess Diana was the target and not one of the other three people in the car.