If anyone
in this assembly, any close friend of Caesar’s, for
him I say that my love for him was just as much
as his. But you demand why I rose
against him, well this is my answer: It is not that I
did not love him, but I loved Rome more.

Would you rather that he kept living, and all of you would have
became slaves, or have him dead, and live as free
men? I cry for him because he did love me. I am glad
that he had good fortune. I honor him for
being brave. But he was too ambitious, and for that I killed him.

Brutus convinces the plebeians that Caesar was not fit to be the ruler. This shows an example of betrayal because Brutus was a friend of Caesar but killed him. I claims that he killed him for the people of Rome and in order to "save" the people he had to "get rid of the person who was creating (or going to create) problems for them. He betrayed his friendship and loyalty to Caesar for an another. He could've stayed by Caesar's side and did not interfere with how he rules and stayed loyal to him, but he betrayed him by killing him.
*Kake