In Julius Caesar, it is obvious that Brutus is not an honorable man. He broke trust and that alone is not possibly honorable. How is turning your back on a so called friend okay? If Brutus was honorable he wouldn't have been so easily persuaded by Cassius to go as far as committing a murder. Brutus did want he thought was best for Rome, but overall was disloyal and committed a huge sin in the process.
Loyalty in a friendship is very important and sadly that's something Brutus doesn't have. Sure he might have been loyal to his country, but is that really an excuse to kill someone? He loved Caesar as a friend, but was so easily set back by Cassius. Who had obvious dislike for Caesar. “Yet I see thy honorable mettle may be wrought from that it is disposed”, was said by Cassius himself intended toward Brutus! Meaning his honorableness and loyalty to someone can be bent and persuaded so easily. Again Cassius says, “If I were Brutus now and he were Cassius, he should not humor me”. Clearly what Brutus did was wrong, even the so called “villain” believed so too.
But wait, let's take a step back! Brutus did want what was best for his country more than anything. “But his ambition—for that, I killed him” was the excuse Brutus gave to the people for killing Caesar. Basically meaning, he feared that Caesar's ambition would hinder the countries fate. Weirdly though, Brutus does admit that Caesar was good for the people. So wouldn't that make Caesar good for Rome too? And wouldn't Brutus be contradicting himself? Being that without citizens, there would be no Rome.
Although Brutus truly believed that his intentions would better his country, murder is still never right. Especially not on an innocent man/women you call your friend. Yes, that's the solution, kill for better! Then also for him to take full responsibility in joining the stabbing shows that he has no shame. Hath he no heart for his wrongfully accused friend?