Her question wasn't entirely unexpected. This was the way it had always been between them. But if there's one thing River hates above all else, more than her stolen childhood or the place where her story ends, it's hurting the Doctor. Even mostly apart, they've been together long enough for her to see the toll of each loss.
She stepped closer, locking her fingers tightly around the hand in her own, and smiled as she leaned in to kiss her. "No more spoilers."
It was barely more than a whisper, but the meaning behind it was clear enough. She remembered going to The Library, and a little more besides.
"As long as we're here," she still spoke softly, but her tone offered no room for disagreement, "we're on the same page."