One of the tricks to acting Susanna is that she herself is an actor, and a far more subtle one than her goofball fiancé Figaro. Susanna actually charges her personality based on who's in the room with her. In Act 1, she's a spiteful, vicious vixen around Marcellina; a flirtatious older sister to Cherubino; submissive and feminine with the Count but aggressive, self-righteous, and indignant with Basilio.
One of Susanna's greatest moments comes when she joins the Act 2 finale and transforms duet into trio. She really shines in these scenes of topsy-turvy transformation, where everything becomes its opposite and expectations are foiled. Here, the Count and Countess have been having a very serious fight, flinging accusation and name-calling across an up-tempo 4/4, building to the moment when the Count, weapon in hand, flings open the door to the Countess’s closet. He (and she) expect Cherubino to emerge, but Susanna does so instead, bringing into the room with her a calm, unperturbed minuet. With delicious irony she tosses the Count’s passionate words about Cherubino back in his face:
Mora, mora, e più non sia ria cagion del mio penar.
Ah, la cieca gelosia qualche eccesso gli fa far.
IL CONTE E LA CONTESSA
Signore, cos'è quel stupore?
Il brando prendete, il paggio uccidete,
quel paggio malnato, vedetelo qua.
(Che scola! La testa girando mi va.)
(Che storia è mai questa, Susanna v'è là.)
(Confusa han la testa, non san come va.)
Let the boy die! Then he’ll torture me no more.
Such blind jealousy! This jealous man will do something rash.
THE COUNT AND THE COUNTESS
My lord! You seem surprised.
Take your weapon. Kill the boy.
The cherub of hell—he stands before you.
My head is spinning. How can this be?
(How can this be? Susanna wasn’t in there.)
(Both of them are baffled!)
It’s a great moment because her complete control of the situation, her improvisatory genius, leave both Count and Countess dumbfounded. Now, Susanna has a complication relationship with the Count: the two of them wage a fierce battle for control of this castle and everyone in it, and (as with the Countess and Cherubino) the opera is far more interesting if there’s a possibility that Susanna might really be attracted by the Count. I think she knows deep down she’ll never be able to have him on her terms, however, so she consoles herself instead with her great intimacy with his wife -- really, one of the most loving and beautiful relationships between two women in all of opera -- and by commanding Figaro, the Count’s right-hand man.
From the very first scene, Susanna and Figaro have this strongly dominant-submissive thing going on. “Sei tu il mio servo, o no?” she asks him, in their first recitative: “Are you my servant, or aren’t you?” The climax of their love-story, on their wedding-night, is when Susanna beats Figaro, to his great delight. And, perversely, the only time Susanna really expresses the depth of her feelings for Figaro is in her 4th Act aria “Deh, vieni”, which is all another scam—she knows that he’s eavesdropping and that he thinks she’s singing this love song to the Count. For some reason, that little psychological-torture-clause is necessary for Susanna to allow herself to feel the dangerously powerful flood-tide of love she bears for Figaro, an emotion conveyed with genius of simplicity in this ravishing marriage of text and music:
Qui ridono i fioretti e l'erba è fresca,
ai piaceri d'amor qui tutto adesca.
Vieni, ben mio, tra queste piante ascose,
ti vo' la fronte incoronar di rose.
The flowers laugh in the fresh grass....
Come and taste the pleasure of love.
Come, my love...hide with me beneath the stars.
I want to crown your brow with roses.
Hundreds of years later, we are grateful to Mozart and Da Ponte for giving us this incredible character. As an old professor of mine used to say, “There’s a lot of woman there!”