The next day, Frankville shows D’elmont the letter he received from Camilla. Camilla professes her love and fidelity to him, explaining that she has found a new servant willing to transport letters between them. However, she is soon going to be forced to marry Cittolini. Frankville writes back coldly, explaining that he no longer wants to see her.

The two men are interrupted when D’elmont receives a shocking letter: It turns out that he has been tricked. Ciamara (Cittolini’s sister, and Camilla’s stepmother) is the woman who has been pursuing D’elmont. When her servants reported that D’elmont was at the house asking to meet with Camilla, Ciamara posed as Camilla and met with him instead. Since D’elmont had never seen Camilla and had never learned the name of the anonymous Roman woman who was pursuing him, he fell for the trick, believing that Camilla was unfaithful. In the letter, Ciamara explains what she did, and pleads with D’elmont to return her feelings.

D'elmont and Frankville are both delighted to learn that Camilla is not unfaithful. They decide to leverage Ciamara’s desire for D’elmont in the hopes of getting Frankville access to Camilla—this is especially urgent because he needs to explain the cold letter he sent to her.