if we compared the two couples in the play, we would see that both couples share a problem with trust. However, for Benedick and Beatrice, the feelings of hate and distrust come first in their relationship, but then they grow to love each other. While on the other hand, Claudio and Hero experience love at first sight, but then Claudio develops an unwarranted distrust of Hero.
We see in the very first scene just how much Beatrice and Benedick dislike and distrust each other. One excellent example is that when Beatrice learns from the messenger that Benedick has closely befriended Count Claudio, Beatrice refers to Benedick as a contagious disease, as we see in her lines, "If he[Claudio] have caught the Benedick, it will cost him a thousand pound ere he be cured" (I.i.74-76). We especially see how much Beatrice's dislike for Benedick has also turned into distrust when she refers to him as a playboy. When Benedick declares that he loves no woman, Beatrice rejoices in what a relief that is for all womankind, saying that they are spared from marrying an unfaithful man, as we see in her line, "They would else have been troubled with a pernicious suitor" (108-109). Benedick equally shows his dislike for Beatrice when he greets her by referring to her as "Lady Disdain," meaning that he acknowledges her as a person who treats everyone with contempt and mocks them (101).
However, while Beatrice and Benedick appeared to dislike each other in the beginning of the play, they are easily tricked into falling in love with each other by being led to believe that the one loves the other. Their easy persuadability to fall in love shows us that while they appeared to dislike each other, they actually did see each other's merits. If they had not, they would not have so quickly agreed when they heard others speak of their merits.
In contrast, Claudio and Hero both fall in love at first sight. Claudio refers to Hero as "the sweetest lady" he ever "looked on" (I.i.160). Similarly, when Prince Don Pedro woos Hero in Claudio's name, Hero very quickly accepts and is seen whispering in his ear that she loves him, as Beatrice points out in her line, "My cousin tells him in his ear that he is in her heart" (II.i.278-279). However, despite how sweet, virtuous, and modest Claudio believed Hero to be, he is very easily tricked into believing that Hero is unfaithful by the morally questionable Don John. When Don John tells both Claudio and Don Pedro that he has seen Hero be unfaithful, Don Pedro has enough sense to instinctively disbelieve Don John and declare, "I will not think of it" (III.ii.100). However, neither Claudio nor Don Pedro continue to listen to their instincts and decide to disgrace Hero in the church before the congregation. Claudio even calls Hero an "approved wanton," meaning a "proved whore," showing us just how much he has grown to distrust Hero.
Hence, if we compare the two couples, we see how similar the two couples are but also that their situations exactly mirror each other's.