Jace hasn’t ever had trouble with relationships before.
First of all, he’s charming. He can basically just look in someone’s direction the right way to catch their attention, and he can feel their eyes on him when he walks away. Usually he’s the one to flirt for information on missions, because he’s great with guys and girls. And he’d rather not see his little sister being stared at by creepy men.
Second of all, Jace has never been in love before. He’s had crushes, sure, and he’s looked at certain pretty people and wanted to kiss them, but he’s never felt butterflies or anxiety over the thought of being turned down. And up until now, he’s always assumed that it was because he’d never been turned down.
But then he met Simon, and now he knows.