In Shakespeare's Julius Caesar, Brutus speaks to the Roman crowd in an attempt to explain to them why Caesar had to be assassinated, and why he chose to be a part of the conspiracy.
From his speech, we learn that Brutus loved Caesar "no less" than the dearest friend of Caesar. He joined in the conspiracy not because "...I [Brutus] loved Caesar less, but that I loved Rome more."
We learn that his motives were pure, in a sense. He joined with the conspirators because he was worried Caesar would become a tyrant and turn the listening Romans into slaves instead of free men. Brutus says he "slew" Caesar because of Caesar's ambition.
Brutus is noble and loves his country, and does his best to serve it. He did not kill Caesar out of any selfish motives.
He convinces the crowd. When he asks the crowd if anyone of them want to be slaves, don't want to be Romans, or don't love their country, the reply is "None, Brutus, none!" When Brutus offers his life whenever Rome should be pleased to have his death, the response is "Live, Brutus! Live, live!"
Brutus is shown to be an honorable man by his speech, and, although his success is only temporary, he does manage to convince the crowd that Caesar's assassination was necessary, and that he was justified in taking part in it.