In Much Ado About Nothing, Shakespeare seems to entwine his theme concerning love with his theme of appearance vs. reality, showing us the one perspective on love found in the play--that love is not what it actually appears to be. We see love portrayed as either apparent or real through both the couples, Beatrice and Benedick, and Hero and Claudio.
Hero, after conning Beatrice into believing that Benedick is in love with her, makes the very astute observation, "If it prove so, then loving goes by haps; / Some Cupid kills with arrows, some with traps" (III.i.107-108). In other words, matches are made purely by chance, and even traps, as we see with Beatrice, can join two hearts together. At the beginning of the play, Beatrice and Benedick appear to hate each other, the reality is that they are actually quite fond of each other and, thus, fall easily into the traps that the other characters set out for them. It has also been argued by Bernard Shaw that Beatrice's and Benedick's love for each other is actually far more sincere because they fall in love with each other's intellect, wit, and charm as opposed to Claudio and Hero who fall in love based on physical attraction (Shaw, "Beatrice and Benedick," eNotes).
Another way that the theme of love correlates with the theme of reality vs. appearance is that, while Claudio and Hero are the first of the two couples to fall in love, their love is love at first sight, and while it appears to be strong, by the fourth act, we see that it is inferior. Neither Claudio's love for Hero nor his strength of character are enough to prevent himself from being duped by Don John, a man he already knows has questionable character. Had he never allowed himself to be tricked, but instead went with his instinctive belief that Hero is chaste and virtuous, he never would have publicly slandered her. But instead, Claudio's love for Hero was developed on her appearances, so when it became apparent to him that she had been unfaithful, he believed that what was real was actually very different. We especially see this paradox expressed in his lines:
What a Hero hadst thou been
If half thy outward graces had been placed
About thy thoughts and counsels of thy heart! (IV.i.103-105)
In other words, Claudio is saying that if only Hero's soul had been as virtuous and beautiful as the rest of her, he would have considered her to be a hero, a very noble and virtuous person. Claudio's change of heart tells us just how much Shakespeare has entwined his theme of love with the theme of appearance vs. reality, showing us the perspective that love is not what it actually appears to be. However, we know that Claudio has been duped and the reality is that Hero is truly as virtuous as she first appeared to be, despite Claudio's temporary change of heart.