When she enters the library, she can't help but being relieved. Henry is okay, he's awake, and she will protect him now that she's here, even if it means her cover will blow up.
"Henry Daniel Mills."
They made a pact, many years ago. Full name, Henry, doesn't mean you're in trouble, it means it's absolutely important you listen to me not to get hurt, okay? And he nodded, with serious eyes and the glint of a smile.
So he gets it.
There's a connection – an instant, he gets it. She has to hide a smirk of satisfaction from Maleficent.