“Isabelle and Sebastian? Hardly. Sebastian’s a nice guy – Isabelle only likes dating thoroughly inappropriate boys our parents will hate. Mundanes, Downworlders, petty crooks…”“Thanks,” Simon said. “I’m glad to be classed with the criminal element.”

“Isabelle snorted, "All the boys are gay. In this truck, anyway. Well, not you, Simon.""You noticed," said Simon. "I think of myself as a freewheeling bisexual," added Magnus. "Please never say those words in front of my parents," said Alec.”

“Oh, for goodness‘ sake,” yawned Isabelle, “Is he really waking us up at this ungodly hour just to prove his love to you or something? Couldn’t he have called? mundane men are such twits.”(Thinking its Simon when the “doorbell” of institute rings)-Isabelle to Clary, pg.188-”

“But that was Isabelle — if there was a boy around and blame that needed to be pinned on someone, Isabelle would pin it on him”

“Really? Are you going to ask him to be your partner?" Isabelle asked. "It's like cotillion, this partners business, except with killing.""So, exactly like a cotillion," said Simon.”

“He looks," Simon had once said to Isabelle, "like he's thinking about something deep and meaningful, but if you ask him what it is, he'll punch you in the face.”