Brutus's defining character traits are his nobility and integrity. He is portrayed as an extremely honorable man who is initially conflicted about joining the conspirators and assassinating Julius Caesar. Despite his positive character traits, Brutus is rather naive, and Cassius easily manipulates him into believing that Julius Caesar is a threat to the Roman Republic. After extensive deliberation, Brutus decides to join the conspirators and assassinate Julius Caesar to prevent him from disbanding the Senate and ruling as a ruthless tyrant.
In act two, scene one, the conspirators arrive at Brutus's home, and Brutus immediately takes a leading role. Brutus demonstrates his resolve by refusing to take an oath, which emphasizes his firm belief in the plot to murder Caesar. Brutus tells the other conspirators,
No, not an oath. If not the face of men,
The sufferance of our souls, the time’s abuse—
If these be motives weak, break off betimes,
And every man hence to his idle bed.
So let high-sighted tyranny range on
Till each man drop by lottery. But if these—
As I am sure they do—bear fire enough
To kindle cowards and to steel with valor
The melting spirits of women, then, countrymen,
What need we any spur but our own cause
To prick us to redress? What other bond
Than secret Romans that have spoke the word
And will not palter? And what other oath
Than honesty to honesty engaged,
That this shall be, or we will fall for it?
Brutus's strong words reveal that he will never back out of the assassination plot and is determined to follow through with the murder. Unlike the other conspirators, Brutus's intentions are noble, and he genuinely believes that he is protecting the Roman populace by assassinating a potential tyrant. Considering Brutus's nobility, honorable personality, and strong words to his fellow conspirators, Brutus is unwilling to turn back on his decision to assassinate Caesar and will accept the consequences of their actions. If Brutus were to turn back, the senators would more than likely consider him a target and take revenge on him for foiling their plot.