Why does Colonel Graff call Ender Wiggins sweet?

Is this the line you're referring to?

"I have no doubt of it. I'll be waiting for you to get here. I watched the vids of what he did to the Stilson boy. This is not a sweet little kid you're bringing up here."

"That's where you're mistaken. He's even sweeter. But don't worry. We'll purge that in a hurry."