Why did Benedick Beatrice and the Friar pretend Hero has died?

In Shakespeare's play "Much Ado About Nothing," Benedick, Beatrice, and the Friar do not pretend that Hero has died. The plot revolves around the false accusation that Hero has been unfaithful to Claudio on their wedding day. This accusation is orchestrated by Don John, the villainous brother of Claudio.

It is Hero's cousin Beatrice who, as a means of helping Hero regain her reputation, feigns grief over Hero's supposed death. To further convince Leonato, Hero's father, of Beatrice's and Hero's innocence, the Friar suggests that they spread the news of Hero's death.