You guessed? You must have been pretty sure, considering you could have killed me."
"I was ninety percent sure."
"I see," Clary said. There must have been something in her voice, because he turned to look at her. Her hand cracked across his face, a slap that rocked him back on his heels. He put his hands on his cheek, more in surprise than pain.
"What the hell was that for?"
"The other ten percent.

Cassandra Clare