In all the three panels he appears in this chapter, Kaneki is shown with that same smile. I can’t tell if it’s fake or not, probably not, for as hard as it is to believe it it may actually be that he’s finally believing someone loved him, and yet, this last panel with the centipede gives us a different intake.
He is happy. She is happy. They are looking at her friend’s wedding from afar, and she is happy too. But let us not forget: he is a ghoul and the One Eyed King - this is what the centipede represents. They are hiding and constantly on the run, still in full and massive trouble. Kaneki’s excessive smiles come in contrast to this last image because probably HE IS the one who’s forgetting precisely this. He’s never been well-loved or, to be more exact, he’s never understood when he was. This is a whole new situation for his psyche, and he doesn’t have a definite approach to this yet. Love makes you blind, they say, and that’s just what is happening here.
He said recently to Amon that he was fighting for ghouls simply because there are many amongst ghouls he holds dear, but he was saying this before he realised just how much exactly they hold him dear in return. He may lose his focus. Even coming to this wedding, though watching it from afar, is terribly dangerous: is you misstep you’ll have the whole CCG at your tail. Would another Kaneki have done it? He’s not reckless. Yes, he infiltrated the CCG labs just to save Akira, but had a full-fledged plan.
Things are not well at all. When we read chapters like these we see the pink parts first and foremost. When Touka’s confession appeared in the same chapter where pretty-evil-boy Furuta announced his master plan, it massively overshadowed exactly this. The centipede is a call back to reality and possibly to negatives events. It represents Kaneki’s strength, but also his desire for revenge as he put fought against Jason - and not casually, I deem, Kiyoko’s mutilation at his hands was also revealed in this chapter.
Kaneki is kind. When he first met him, he let Amon go. Yet he harms, even terribly, those who hurt whom he holds dear. Ayato, anyone? Matters not they’re happily in-laws now, it served the purpose to show us a first glimpse of his dark side. As Haise, He wanted to let Tsukiyama go, but to do so, he threw Kanae/Karren down a skyscraper - you can never stop stepping on other people’s corpses: “The world is like an egg: to let something be born, it must be broken.”, As Eto poetically put it. Kiyoko is this chapter is just another metaphorical corpse. Is Kaneki forgetting this heart-wrenching truth?
He can coldly control his cruelty, but at times, he also can’t. And now Touka gives him the ring of her father who lost his mind seeking revenge for her mother. All the while a lovely centipede reminds us that no matter how clear blue the sky is now, this story is, in fact, a tragedy.