Deepwood Weald i was going to cover that in the hear-me-out portion.

quiet simply put, Hela does not know how to act. any semblance of a happy childhood had been frayed first simply be existing in the place of her birth, torn further with the death of her mother and disappearance of her mother, and stamped out entirely when she'd come to the Nightwalkers. 

part of her is intruiged by the boy, his lightness of speech and action. some of her wants to stay. but when it comes down to it, her fear of failure in front of him is greater. "no." comes her answer, then, followed by a, "goodbye." and then the girl is gone, beelining back toward a place where things make sense.