Characters
You see, I have no plans to break down her morals. I want her to believe in love and virtue and the sanctity of marriage, and still not be able to stop herself. I want the pleasure of watching her betray everything that is important to her.
— Vicomte de Valmont · Dangerous Liaisons

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker wants the woman to retain her belief in love, virtue and marriage while acting against those convictions. The desired pleasure comes from witnessing that contradiction. This is a calculated wish to see someone betray their own values, rather than persuade them to abandon those values first.
Context reviewed