I'll create a scenario before Oro defected where he and Jiraiya had a "Naruto v Sasuke" kind of fight.
It had been quite some time, Orochimaru stood before his rival and friend, Jiraiya. Perhaps friend was the wrong term to use, more like, colleague. They had done a large amount of missions together before, and they became quite well known all around. The even garnered the names, "Sannin" from their encounter with Hanzou of Amegakure. A close one, that was. They had survived, and Orochimaru had gained a new perspective, of course, unbeknownst to Jiraiya. He had seen his morality, it was feeble. He was still weak, and perhaps now, was a good time to test whether or not he would pursue his dream. A dream of..more. He wanted more, from life that is. As it existed now, it was too easily broken. Too easily lost. Orochimaru was the more quiet one of the group, Jiraiya always was the more loud one. With a stoic expression and voice, Orochimaru would address his colleague.
"Jiraiya..you waste away your days looking at women. Doesn't it bother you, what we went through? Don't you feel like we could achieve more? Knowledge, is endless. And together, oh my. Very few would stand in our way..."
He said, his voice carrying a sinister aura with it. He had a motive, of course. And Jiraiya would pick up on it, he was a man of morals.. but was he willing to perish before he had achieved what he really wanted in life? Orochimaru offered him more.
