His Girlfriend

Well-meaning but socially awkward, Kuronuma Sawako is nicknamed "Sadako" by her high school classmates because of her similar hair style with the main character from the horror movie "Ring." She doesn't have friends and goes about her day in quiet. She admires a fellow classmate, Kazehaya Shota, because of his easy-going and friendly nature, but unknown to her, Kazehaya has also been paying attention to her.

Similarities:
-Both are adaptation from romance-shoujo manga
-Female lead falling in love and confess first
-One-sided love and love triangle

Well-meaning but socially awkward, Kuronuma Sawako is nicknamed "Sadako" by her high school classmates because of her similar hair style with the main character from the horror movie "Ring." She doesn't have friends and goes about her day in quiet. She admires a fellow classmate, Kazehaya Shota, because of his easy-going and friendly nature, but unknown to her, Kazehaya has also been paying attention to her.

Both are high school stories in which the FL falls in love with the ML who already has a girlfriend or a crush on someone else.