Constanze, considered to be the first profound female role in Shaffer's work (cf. Thomsen and Brandstetter, 202), turns out rather flat on the screen. In the stage version of Amadeus, which is essentially a two-character play, she has a "minor, underwritten part" (Kakutani, 20), but she appears both womanly and mature, especially towards the end of the play. Although a little careless and flirtatious, as presented in the game of forfeits (Play, 42ff.), she is nevertheless practical, charming, sensuous, and full of joie de vivre. What is more important, she loves her husband dearly and stands by his side through every hardship and humiliation. Both Mozart and Constanze are careless bon vivants, but she is the more responsible of the two and often acts as a substitute mother for her boyish husband. In the word games with the childish Mozart she appears equally infantile; but when it comes to facing unpleasant facts such as financial matters or the relationship between Mozart and his father, she shows female maturity and strength of character.
In the play, the key to the character of Constanze lies in the scenes with Salieri at the end of the first and the beginning of the second act. At first, she is truly shocked and appalled at the thought of selling her body to Salieri for the price of a secure post at court for her husband. He gives her time to go away and think over her decision. When she returns, she is ready to sacrifice herself for her husband, but she does not pretend willingness. Her directness is shocking to Salieri:
CONSTANZE [flatly]: Where do we go, then?
CONSTANZE: Do we do it in here? ... Why not?
[She sits, still wearing her hat ... Deliberately she loosens the strings of her bodice, so that one can just see the tops of her breasts, hitches up her silk skirts above the knees, so that one can also just see the flesh above the tops of her stockings, spreads her legs and regards him with an open stare.]
[Speaking softly] Well? ... Let's get on with it.
[For a second SALIERI returns the stare, then suddenly looks away.] (Play, 59)
Salieri is so appalled at her and his own behaviour that he rejects her sexual offer and sends her away. Hearing this, Constanze is so humiliated and hurt in her female pride that she gets furious and insults Salieri, calling him a "rotten shit" (Play, 60), thus ruining every chance for Mozart to obtain the desired post. This is a very feminine and emotional reaction, but it also shows that Constanze realises she has gone too far in offering herself to Salieri in the first place. From this conflict between sacrifice and dignity, she emerges as the moral victor, although she loses the chance for a stable family income.
In the film, the seduction is practically omitted. When Constanze brings Mozart's manuscripts to Salieri, he merely tries to flirt with her a little, but he forgets her immediately and completely after turning his attention to the manuscripts. While he is studying them, he experiences a kind of musical orgasm (see quotation), which is perhaps a substitute for the deleted seduction scene. This hypothesis is confirmed by Abraham's acting in this scene, in which his excitement bears a strong resemblance to sexual stimulation. Although the scene of Salieri studying the manuscripts can also be found in the play, it has an extended function in the film. Unfortunately, the deletion of the seduction diminishes the role of Constanze, who is now acting childishly and innocently, thus losing much of her female strength.
Generally, the stage Constanze is a more adult character than her screen version played by Elizabeth Berridge. She is more complex in her relationship with Mozart, being at once his lover, his mother, and his companion. She submits to Mozart's sexual wishes, for example scatological riddles or "botty smacking" (cf. Play, 52), and she is jealous of his pupils with whom he deceives her. In the film, Constanze's eroticism is rather infantile, restricted to the Rococo costume accenting the lines of her body, and to her sulky mouth. Very often, she gives the impression of a dressed-up child, as, for instance, in the scene with the manuscripts, where she is more sensitive to the sweets in front of her than to Salieri's sexual allusions. While in the last part of the play Constanze is described as wearing poor clothes and looking worn out, in the film she remains an immaculate and colourful Rococo bird till the very end. This again presents her as an expensive toy rather than a companion to her husband during hard times. She does not participate in the Mozart-Salieri relationship anymore, but is pushed into the background and almost becomes one of the minor characters.