After Leonato and his brother exit, Benedick walks up to the Prince and Claudio. Although they still believe that Hero was having a relationship with Borachio, Claudio and the Prince are certainly not happy about what has occurred. So, they greet the usually witty Benedick because they think that he can cheer them up. Benedick, however, has no intention of using his wit. Rather, he intends to use his sword (line 125). The Prince and Claudio, though, think that Benedick is just joking. Even after Benedick directly asks Claudio to meet him in a challenge (a duel), Claudio responds as if it is just another joke:
Well, I will meet you, so I may have good cheer. (148)
Claudio is saying that he will gladly meet up with Benedick so long as Benedick provides him with a good dinner. Don Pedro also believes that Benedick is jesting, and launches into a little speech about how Beatrice criticized his wits. Benedick, though, is serious and does not engage in a witty exchange. After Benedick exits, the Prince and Claudio are quite surprised by the seriousness of Benedick's challenge and find it difficult to believe. For a solider to challenge one of his own close companions in such a serious way was practically unheard of. Don Pedro, though, believes he knows why Benedick is behaving in this manner:
What a pretty thing man is when he goes in his doublet and hose and leaves off wit! (189-90)
The "doublet and hose" refers to fines clothes, the type of clothes a man will wear when he goes to woo a woman. Thus, the Prince is asserting that Benedick's affections for Beatrice are so strong that he has become witless, that he is not thinking clearly. Thus, they excuse Benedick and believe that he will no longer wish to challenge Claudio once his wits are restored.