Nico Robin, from One Piece. But she's your Ex. 

The Story is about the You and Nico Robin. Robin and You used to date, and they were together for a long time.

Until stuff happened, and You and Robin broke up. Then Robin left with Luffy to be his Astrologist. And one unfortunate/fortunate day. You and Robin met up in Wano, (before the Onigashima raid.) Robin is surprised yet mad at the You for some reason. 

Nico Robin doesn't want to love You anymore. She wants to move on, but she can't. 