During a hunting expedition, Osburgo and Valdeburgo encounter Arturo, but are aware that Alaide's cabin is close by. Osburgo begs him to return for his wedding to Isoletta, but he refuses, declaring that he does not love her. He asks Valdeburgo to meet his true love, after which he promises that he will never see her again if Valdeburgo judges her unworthy. The pair approach the cabin, from which Alaide emerges. Upon seeing her, Valdeburgo hails her and almost calls out her real name, but Alaide stops him. Valdeburgo tells Arturo that —for reasons he cannot reveal— Arturo must renounce any intentions toward Alaide. She cannot ever marry Arturo. Thinking Valdeburgo is his rival for Alaide's affections, Arturo is about to attack him with his sword, but he declares that he is not a rival. (Trio: first Valdeburgo "No: non ti son rivale; / non io ti tolgo a lei" / "No: I am not your rival; then Arturo "Ah, if he is not my rival, / What does he wish of me"; then Alaide "No, you have no rival".) Alaide begs Arturo to leave, promising that she will see him again: "Your life, Arturo, matters to me as my own". Both Alaide and Valdeburgo urge Arturo to leave.