サクラ、サク。

Saku Fujigaya has always felt like a background character, unnoticed and unremarkable, until a chance encounter on a train changes everything. When a kind stranger named "Sakura" helps her during a moment of need, Saku is inspired to pay it forward, vowing to help others just as she was helped. Years later, in high school, she meets Haruki Sakura, a boy with a familiar name and an older brother, Ryosuke, who might be the key to her past. As Saku navigates the complexities of friendship, gratitude, and budding feelings, she begins to find her own voice and place in the world. (Unreviewed summary by Grok 2)