Brutus told that he loved Caesar but he loved Rome and Roman people more. He killed him because he was becoming too ambitious. If he would become the king then he would make everybody his slaves. He would bring tyranny to our country 'Rome '. He killed Caesar not for his personal jealousy or something, he killed Caesar for the sake of our nation.
The conditions are:
1) Antony had speak at the same pulpit where Brutus had to speak.
2) He would say that Brutus and other conspirators has allowed to speak in the Caesar 's funeral.