All that's really significant from the next chapter (from the top of my memory btw, so it might not be perfectly accurate, LOL)...
Flashback chapter. Kaoru's friends all know she likes Reiichi and nobody knows why. Her attempts to confess always seem to fail as well. Risako meets Reiichi in the library alone one day, and Reiichi mentions something about how it's surprising that she and Kaoru get along so well, since Kaoru is clumsy and always causes trouble for people. Risako confesses that she actually admires Kaoru's bright sides, but tells Reiichi to keep it a secret between them. Reiichi visibly admires Risako's beauty here (and develops a crush on her). IIRC, on graduation day, Kaoru laments over having her feelings gone unnoticed this entire time, and decides to go confess to Reiichi.
When she finds Reiichi, he's alone in a classroom with Risako, so she decides to eavesdrop. Reiichi confesses to Risako, which catches her a little bit off guard. Before she gives him an answer, she asks Reiichi what he thinks of Kaoru. Reiichi mentions that they were raised together, so they have a familial relationship, but he isn't sure if they're exactly considered super close. Risako somewhat insists that lately, him and Kaoru have been getting closer (to his doubt), and then mentions that it would be too complicated for them if Reiichi and Kaoru were too close. Reiichi hesitates for a second, but says he'll increase the distance if Risako agrees to date him, to which she accepts.
Reiichi is incredibly overjoyed at this and the two leave the classroom... only to find out that Kaoru has been listening this whole time. Risako sends Reiichi home first so she can talk to Kaoru alone, and her expression implies that she was expecting Kaoru to be there all along. When Reiichi leaves, Kaoru asks why Risako and Reiichi are going out. Risako says it's because he confessed to her first and that those two had the chance to speak in the library. Kaoru asks if Risako secretly had a crush on Reiichi this whole time, but she denies it, and tells Kaoru that she only agreed to date Reiichi because there wasn't any reason to turn him down. Kaoru is upset by this, and says that she would've preferred it if Risako's reason for going out with him was because she actually liked him, even if she had to lie to her.
I don't even know what to think anymore.