Why did Horatio promise at the end of the play?

At the end of Shakespeare's "Hamlet," Horatio promises to tell Hamlet's story and ensure that the truth of the events leading to the prince's tragic demise is known. This commitment reflects his loyalty to Hamlet and the desire to honor his friend's memory by revealing the corruption and betrayal that plagued the Danish court. By promising to speak, Horatio also takes on the role of a witness to the tragic consequences of ambition and revenge, emphasizing the importance of memory and narrative in understanding the past.