Complex sentence: Once they are alone Jessica tries to convince Hugo that he was taken in by Hoederer's point of view, but he twists this around saying that it is all the more the reason to kill Hoederer since he could convince others.
Split into simpler sentences: Once they are alone Jessica tries to convince Hugo that he was taken in by Hoederer's point of view. But he twists this around saying that it is all the more the reason to kill Hoederer, since he could convince others.