On the way to the pool, Saki remembers the one day she and her mom went to the beach. She had a ton of fun, but more importantly, it appears she met Yuuta that day, and her mom and his dad also met. Now, years later, Saki has lived with Yuuta and gotten to know what a kind and special person he is, and admits in her thoughts (and in her diary) that she’s attracted to him.
While watching Saki have fun at the pool, smiling brightly and even laughing with the others, Yuuta looks back fondly at all the times she’s smiled and laughed since they met (or rather reunited, though it’s not clear whether he remembers). He comes to the same conclusion she did: he likes her.
After Saki thanks Yuuta for suggesting they go to the pool with Maaya and the others, Yuuta is ready to say something to Saki, but is interrupted by th dreaded Surprise Anime Fireworks, which either make it so someone can’t hear the other person’s confession, or in this case cause the other person to speak first. Saki later hopes Yuuta didn’t see her hands trembling when she called him “oniisan” for the first time.
The fireworks were the perfect buildup for a confession of love, but both Saki and Yuuta believe it’s in everyone’s best interest to stamp out those sparks and forget about them. They don’t want to cause trouble for each other and especially their parents.
Saki also re-reads her diary and decides she was too forthcoming about her feelings for Yuuta, so she decides to stop writing in her diary, and limit such thoughts to her head from now on. She tosses away the key so even she can’t unlock it, then has her long hair—something she had in common with Shiori—cut short.
She returns home with her new ‘do just as her mom is showing Yuuta a picture of her when she was little, with the same ‘do (albeit before she bleached it). While I respect Saki’s gesture and the resolve behind it, I imagine it won’t be that simple.
