Cécile declines Valmont's initial request that she steal the key to her room from her mother in Letter Eighty-eight. Thus, in Letter Eighty- nine, Valmont is forced to resort to trying to apply pressure on her through the Chevalier Danceny. He tells the chevalier that his affair is progressing much more slowly than necessary, and if he will only convince Cécile to trust him (Valmont), things will move along at a much faster pace.

The Présidente de Tourvel begs Valmont to go away again in Letter Ninety. She claims that his presence only makes her suffer. Valmont's response (Letter Ninety-one) is yet another strange combination of accusations and apologies. He ends by praying that she will not make him go away.

Danceny writes back to Valmont (Letter Ninety-two) to express his worries that Cécile has stopped loving him and to ask Valmont to help him secure her affections again. He then composes a letter to Cécile herself (Letter Ninety-three), in which he writes that he is very upset to hear how little trust Cécile shows Valmont. Danceny worries why she refused to see him and whether she has stopped loving him.

Cécile's reply is anguished and confused (Letter Ninety-four). She does not understand what Valmont can have told Danceny. She assures Danceny that she continues to love him and that she will do all in her power to bring about their reunion. She then writes to Valmont to tell him (Letter Ninety-five) that she consents to bring him the key to her room.

Valmont is enjoying toying with the Présidente, but he is even more excited about the deflowering of Cécile Volanges, which he has recently accomplished. He tells the Marquise (Letter Ninety-five) that he snuck into her room one night, using the key he had procured from her, and had his way with her.

Cécile, in turn, writes to the Marquise (Letter Ninety-seven) to report the incident and beg her for help. Madame Volanges also writes to Merteuil (Letter Ninety-eight) to ask for advice. However, she assumes that her daughter's unhappiness is due to separation from the Chevalier Danceny and not Valmont's nighttime activities. Volanges asks whether it would not be better to allow Cécile to marry Danceny instead of Gercourt, since it is obvious that the two young people love each other very much.