Act II

Evening is falling and Despina persuades the sisters to give the suitors another chance. Dorabella confesses her curiosity, Fiordiligi is carried along and a liaison is arranged, each girl choosing the stranger they find the more attractive – in fact, the other’s partner: Dorabella has set her sights on Guglielmo, Fiordiligi on Ferrando. In the moonlit garden the Albanians sing a serenade, but when the sisters enter, the four lovers find themselves tongue-tied and need some prompting from Don Alfonso and Despina. Ferrando and Fiordiligi go for a stroll, leaving Guglielmo alone with Dorabella. She quickly succumbs to his seduction, exchanging her miniature of Ferrando for a little silver heart Guglielmo hangs around her neck. They go into the house together. Fiordiligi rushes in pursued by Ferrando. Tortured by her conscience, she begs him to leave her alone.

The men meet in secret to compare notes. Guglielmo is delighted, Ferrando heartbroken and furious at his friend’s success with Dorabella. Guglielmo blames the whole affair on the fickleness of womankind. Don Alfonso appears and reminds him that the wager is not yet won.

Despina congratulates Dorabella on her exciting new romance but Fiordiligi is appalled. Dorabella tells her sister plainly that she is ready to leave Naples with her new lover that very night. Fiordiligi is determined to stay true to Guglielmo and conceives a desperate plan to follow him, disguised, into war. She is spied on by the three men and Ferrando falls passionately at her feet. Fiordiligi loses the battle and admits that she has fallen in love with her new admirer. Once she has gone, Guglielmo gives vent to his fury and nearly comes to blows with Ferrando. Don Alfonso intervenes; the best revenge, he proposes, would be to take the test to the limit and stage a false wedding with the two girls. Despina confirms that the sisters are willing and the men agree.

Despina organises a hasty wedding feast and the lovers enter and make a toast; let the past be drowned in the wine. Don Alfonso announces the arrival of a Notary with the marriage contracts ready to sign (Despina again). The ink is hardly dry on the paper when a march is heard outside and Don Alfonso tells the terrified girls that their lovers have returned. They bundle the Albanians and the Notary into another room. Guglielmo and Ferrando quickly change back into their uniforms and re-enter to greet their fiancées. The ‘Notary’ is discovered and unmasked, to the sisters’ astonishment, then Don Alfonso drops the signed contracts at the men’s feet. They pretend to search furiously for the girls’ new lovers and the sisters beg for mercy. The whole deception is now revealed. Don Alfonso wins his wager.