Brutus agrees to go along with the plot because he thinks that it will honestly be better for the Roman Republic.
Cassius is convinced by brutus to join his plot
Cassius convinces Brutus to join the plot to assassinate Julius Caesar by appealing to Brutus's sense of honor and patriotism and by highlighting Caesar's growing power and ambition. Cassius also plays on Brutus's fear that Caesar's power will diminish the Roman Republic.
Cassius!
Cassius & the rest of the conspirators were eager to have Brutus' support because he was honored by many people at the time; they thought that this would give their cause more merit. Also, they figured people wouldn't be as quick to question their motives if an honest man like Brutus was involved.
his name would help to make the assassination plot into something worthy and virtuous.
Brutus joins the plot to assassinate Julius Caesar with Caesar's dying words being 'Et tu Brute'
In Shakespeare's play, Cassius is sounding Brutus out to see if he is sympathetic to the plot against Caesar.
They want Brutus to help them.
Casca comments that the noble Brutus's participation in their plot will bring worthiness to their schemes, for "he sits high in all the people's hearts, / And that which would appear offence in us / His countenance, like richest alchemy, / Will change to virtue and to worthiness"
Brutus is so blinded by his love of the country that he doesn't see faults in his assassination plan.
acas
Julius Caesar knew a guy called Brutus because he had an affair with Brutus' mother and Brutus would sometimes go to Julius' house. A rumour then began that Brutus wanted to kill a politician called Pompey, Julius helped Brutus out saying it was all a lie. Then in 44BC(the year Julius was killed), Brutus was part of a plot to murder Julius. Brutus played a major role, distracting Julius so someone could stab him in the neck.