Giunse alfin il momento - Deh vieni non tardar- Wolfgang Amadeus Mozart

The aria appeared just as Susanna and the Countess were about to succeed in their scheme. They plan to trick the count into thinking that Susanna is willing to meet him, and the countess will meet him pretending to be Susanna, thereby exposing the count's infidelity. Suzanne is alone in the garden, waiting for the moment to execute her scheme, pretending to sing a love song to her lover (who is actually Figaro)