Hijiri "See-chan" Honjou
About
Wikipedia
After knowing Chihiro's tragic past, she suggested Shiina not to be with Chihiro because (according to chapter 33) she is afraid that Chihiro will abandon Sakuya and return to Sakura.
From chapter 34, the manga revealed that Hijiri's crush was Shizuka, a math teacher and her homeroom teacher since first grade of high school.
From chapter 43, the manga revealed that Hijiri and Saki, a man serving her, likes each other.
She married Saki in the end.