The gender roles assumed by all of the characters in the play (including Beatrice and Benedick) are poses. As such, they reinforce a second main theme of Much Ado, the disparity between reality and appearance. All of the main characters in the play are either deceived by others and/or take part in a plot (or plots) intended to deceive others. Misperception and "misprising" abound in Much Ado. A crucial instance of the gap between reality and appearance occurs at the start of Act IV, when Claudio denounces Hero and says:

O Hero, what a Hero hadst thou been,
If half thy outward graces had been placed
About thy thoughts and counsels of thy heart!
But fare thee well, most foul, most fair! Farewell,
Thou pure impiety and impious purity!
(IV.i.100-104)

At this juncture, the misled Claudio compares Hero to a "rotten orange," having only the "semblance of honor." Because the audience knows that Claudio has been hoodwinked by Don John, these words turn against the youthful suitor. Claudio's concern with how his honor appears to others (that is, to other males) imparts a cruel edge to his repudiation of Hero (which he carries out in public), suggesting that there is something rotten beneath Claudio's own skin. The devices of eavesdropping and hearsay that propel the narrative line of the play are entirely congruent with this theme. Indeed, the word "nothing" in the play's title is a homonym for "noting" which, in Elizabethan slang connoted "eavesdropping."