Ramiro discovers Arminda and upbraids her for her inconstancy. When she refuses to listen, he departs, but not before promising revenge upon his rival. Belfiore enters in some distress, muttering that he has had no peace since he found Sandrina. Arminda overhears and confronts him, then leaves ("Vorrei punirti indegno"). Sandrina encounters Belfiore, and nearly betrays herself as Violante when she asks why he stabbed and deserted her. Belfiore is surprised by this outburst and once again sure that he has found his love, but Sandrina quickly reconstructs her disguise. She explains that she is not Violante, but that those were the Marchioness's dying words. Belfiore is nonetheless entranced, since "Sandrina" has the face of Violante, and he begins to serenade her ("Care pupille"). The Podestà interrupts them, and after mistakenly taking the Podestà's hand instead of Sandrina's, Belfiore retreats in embarrassment.