Other mistake: When Sebastian and Ronald are fighting by the roadside, you can see the same man in red shorts and a black shirt, with a white jumper tied round his waist run past them about four times. (01:23:00 - 01:24:10)
Continuity mistake: In the final scene where Annette is driving the Jaguar and having flashbacks, watch as she drives past lovely rolling hills and pastures. Cut to a helicopter shot of her driving the car along a New York freeway (FDR I think...) This mistake has been confirmed by the director. (01:33:35)
Kathryn: So I assume you've come here to make arrangements, but unfortunately, I don't fuck losers.
Trivia: Contrary to what some people think, Ryan Phillippe and Reese Witherspoon didn't meet while filming this movie; they were already dating. The director, Roger Kumble, asked Phillippe if they could have dinner with Witherspoon and offer her the role of Annette.
More questions & answers from Cruel Intentions
Answer: A bit of both. I believe that Ronald did love Cecile. But I also believe that Kathryn manipulated him in such a way and so much that he eventually gave in to his masculine tendencies. He's only human, after all. He wasn't anticipating Kathryn telling anyone, let alone Sebastian finding them in the act.
ChristmasJonesfan