Don John, the Prince's bastard half-brother, uses the information that Borachio learned from eavesdropping to cause trouble. Don John walks up to the disguised Claudio and asks him if he is Benedick (although Don John knows that he really is Claudio). In fun, Claudio claims to be Benedick. So then Don John tells him that Don Pedro loves Hero and is wooing Hero for himself (line 142). Claudio becomes jealous and angry and walks sulkily away.
Later, though, Claudio tells Benedick about Don Pedro, and Benedick then tells the Prince himself. Don Pedro then simply walks up to Claudio and reveals that he has won Hero in his name and that Hero is willing to be his bride (lines 260-62). Don John's villainy resulted only in making Claudio angry, and even that did not last for very long. Don John had wanted to hurt Don Pedro and cause problems for him. In that, Don John was unsuccessful. His villainy failed.