What irony occurs at the end of Act III Much Ado about Nothing?

The irony at the end of Act III of Much Ado About Nothing comes from the revelation of Don John's deception and the subsequent reconciliation of Claudio and Hero. Claudio, who has been tricked by Don John into believing that Hero is unfaithful, publicly accuses her of infidelity during their wedding ceremony. However, Beatrice and Benedick uncover the truth and expose Don John's villainy, leading to Claudio's realization of his mistake and heartfelt apology. The irony lies in the fact that Claudio's initial suspicions and accusations against Hero were based on false information and misunderstandings, while the truth about Hero's innocence and Don John's treachery ultimately prevails, bringing about a resolution and reconciliation between Claudio and Hero.