Ai Fuyuumi

One of the protagonists of the Ore no Kanojo to Osananajimi ga Shuraba Sugiru series of light novels. Ai knows protagonist Eita Kidou back when they were children; falling in love with him and making him sign a makeshift marriage registration. Since then, she has been convinced she is Eita's one true love. When they meet again as teenagers, Ai learns there are other girls vying for Eita's affections, so Ai is determined to make Eita acknowledge her as his true girlfriend.