Jayne never said Crazy's name. Not even to himself. Not if he could avoid it.
He used to, once in a while. Then he started noticing how easy it was to say. Not to mention how his voice sounded different saying it. So he stopped.
There were plenty of other things to call her. Reaver-Killer, Crazy, Weapon, Moonbrain, Girl.
Problem with that last was it should rightly be Woman. He tried it out down in his bunk, but that made his voice sound funny too.
She knew why. She looked into his eyes, saw right into his soul.