Impossible
"You really do ask the impossible." she murmured, fingertips pressed into the slightly frosted glass. "You attempt to break my heart and resolve at every possible turn."
Jareth merely pulled his hands back from her, allowing her a much needed moment of gazing at the last member of her family that didn't see her as a freak. "Do you really want to leave him behind? The boy who still holds your hand and looks at you as if you hung the moon? The boy who defends your differences and oddities? Could you really give him up for an eternity? Because you cannot have him back should you choose a life as my queen." he whispered harshly, as if reliving some old hurt of his own.
"Ours is a land of monsters and myth, my love." she replied, just as softly. Just as sadly. "Ours is no place for a young boy. He deserves a chance as what I could never have."
"And what is that, precious thing?" Jareth asked her, stepping forward so that he could gaze though the glass with her.
"A life." came her simple reply. "A real one. Not this fractured, half-shadowed existence; riding the line of real and make-believe. Where spirits wave at you from behind the faces of neighbors, and you don't know to which you are acknowledging. He deserves the chance to grow up. To see the world as pure and beautiful and maybe even a little fantastic."
"How fantastic do you think his world will become," Jareth began, almost regretfully. "When his sister disappears, never to be seen again?"
Sarah was quiet for a long moment, just staring at her brother. "I'll spare him that pain, Jareth. I'll make him forget that I ever existed at all."
"You would do that for the ones you love? For the ones you are leaving behind?"
"It's no more than you did for yours, when you took up the title of king."
Note: A chapter since it's technically tomorrow here. Enjoy. I have another write-night going, but I'm not having much luck working on anything so I'm updating instead.