It was Yuffie who first noticed the goldenprettyshiny ring in Kairi's left hand. She squealed and cartwheeled before going off to tell everyone that their Princess had gotten married.
It was Tifa who did the inevitable and looked for a matching ring in Sora's finger. He had after all searched the worlds for the redhead so many years ago. She was baffled when under the gloves the spiky haired boy continued to use, she found no golden band.
It was Leon who, after much prodding from a ninja, gave in and, reluctantly, turned to the silver haired boy's hand, because even if his methods were not the greatest, he had still done everything to protect Kairi. But there was nothing on Riku's hand.
And it was Cid who declared that golden, pretty, shiny rings must be in fashion in Destiny Islands after the redhead refused to say anything about the band around her finger. After all, no one would hide something like marriage, least of all a Princess of Heart.
It was only after much thinking that Donald and Goofy remembered that Sora had also searched for Riku during his adventures, that the brunet had traveled the worlds for his friends, as in plural. And after Kairi had been safe in the islands, Sora continued to look for the silver haired friend he had left in the darkness.
Similarly, it was the King who remembered that Riku had stayed awake and sacrificed everything for the blue eyed boy during the long year that everyone forgot him. How it was Sora who was the light to Riku's darkness, and how one could not exist without the other.
However, despite everyone puzzling over it, it is only Kairi who notices with a smile the goldenprettyshiny ring that hangs on Sora's necklace or the goldenprettyshiny ring that dangles from Riku's left ear. After all, theirs had never been a conventional fairy tale.