The book ends at the moment when Henry and Keiko meet again after so many years, and he starts to say the one Japanese phrase he knows to her—the one Sheldon taught him so many years earlier that means, "How are you today, beautiful?"
They stood there, smiling at each other, like they had done all those years ago, standing on either side of that fence.
"Oai deki te…" She paused.
"Ureshii desu," Henry said softly. (52.29-31)
It may seem like an odd place to end, especially since we've been waiting for these characters to get together for the entire book. But the ending isn't designed to leave readers hanging or to cheat them out of a romantic scene—it's meant to show just how little has changed between Henry and Keiko even after decades apart. They greet each other with familiar affection as though no time has passed at all. Aw.