Is there some particular reason that you're here?" ...
"Not this again."
"Not what again?" said Clary.
"Every time I annoy him, he retreats into his No Mundanes Allowed tree house." Simon pointed at Jace.

Even in half demon hunter clothes, Clary thought, he looked like the kind of boy who'd come over your house to pick you up for a date and be polite to your parents and nice to your pets.
Jace on the other hand, looked like the kind of boy who'd come over your house and burn it down just for kicks.

You look happy," he said to Clary. He swiveled his gaze to Jace. "And a good thing for you that she does."
Jace raised an eyebrow. "Is this the part where you tell me that if I hurt her, you'll kill me?"
"No," said Simon, "If you hurt Clary, she's quite capable of killing you herself. Possibly with a variety of weapons."
Jace looked pleased by the thought.

Well, I'd certainly hate to interrupt your pleasant night stroll with my sudden death."
He blinked. "There is a fine line between sarcasm and outright hostility, and you seem to have crossed it. What's up?

Do you remember back at the hotel when you promised that if we lived, you’d get dressed up in a nurse’s outfit and give me a sponge bath?" asked Jace.
"It was Simon who promised you the sponge bath."
"As soon as I’m back on my feet, handsome," said Simon.
"I knew we should have left you a rat.

But that's not what you said when she walked into the room," said Simon quietly. "You said, 'Why didn't you ever tell me I had a brother?'"
"I know." Clary yanked a blade of grass out of the dirt, worrying it between her fingers. "I guess I can't help thinking that if I'd known the truth, I wouldn't have met Jace the way I did. I wouldn't have fallen in love with him."
Simon was silent for a moment. "I don't think I've ever heard you say that before."
"That I love him?" She laughed, but it sounded dreary even to her ears. "Seems useless to pretend like I don't, at this point. Maybe it doesn't matter. I probably won't ever see him again, anyway."
"He'll come back."
"Maybe."
"He'll come back," Simon said again. "For you.