Adding to the holiday merriment of many Renaissance comedies is the inclusion of songs and dance. Out in Leonato's garden, the singer Balthasar performs a tune for Don Pedro, Leonato, and Claudio (beginning at line 56). This particular song is actually about men who are unfaithful to their ladies, but the song advises the ladies not to sigh or cry about it. Instead they should "blithe and bonny" (happy and full of good spirits) and sing "hey nonny, nonny" (71). This last phrase is nonsense. The world may be harsh and unfair, but one should try to enjoy oneself anyway.
After the song, Don Pedro begins his plan. Off to one side, Benedick hides behind a bush or tree. But Don Pedro and the others know that he is hiding and is eavesdropping in on their conversation. Don Pedro and his two companions have created an elaborate fiction -- a pack of lies, actually -- in which they claim that Beatrice has declared that she is hopelessly and madly in love with Benedick but that she is afraid to tell him of her feelings because she knows that he will only scorn and ridicule her.
Claudio uses hunting and fishing metaphors as he catches a glimpse of Benedick out of the corner of his eye and whispers to his companions what he sees. Benedick is like a sitting "fowl" -- a bird who remains motionless so that he is an easy target for a hunter (line 87). A few lines later Claudio says, "Bait the hook well. The fish will bite" (101). Like a hungry fish that is all too eager to bite down on the worm hanging from the fishhook, Benedick is clearly eager to gobble down the words spoken by Don Pedro and the others.
During their talk about Beatrice, they describe her with words like virtuous and wise (lines 144-46). These are the very words that Benedick had just used in describing the ideal wife. Benedick, of course, would agree.
Claudio also adds to the conversation by declaring that Beatrice is so extremely sad and unhappy that it is affecting her health and making her quite sick. Benedick, naturally, would feel quite miserable about making Beatrice feel this way.
Don Pedro ends the staged conversation with the following:
I love Benedick well, and I could wish he would modestly examine himself to see how much he is unworthy so good a lady. (184-86)
Don Pedro is saying, in essence, that Benedick is guilty of a large fault that is not only causing harm to Beatrice, but it is also causing harm to himself.
Benedick's scorn, wit, and ridicule have been a means by which Benedick has shielded himself from emotional hurt. But this scorn and wit have also prevented him from realizing his own true feelings regarding love and regarding Beatrice.