It could be a jealous rival. Maybe there's another ninja who has feelings for Sakura and is trying to keep her away from Sasuke. So Sasuke has to catch her to prevent this rival from taking her away.
Well, it could be a story where Sasuke saves Sakura from someone else who might be a threat. Maybe it's an enemy from another village or a rogue ninja. Sasuke, with his powerful skills, steps in to protect Sakura.
Well, it could be a new character introduced in the fanfic. Maybe a mysterious stranger who has some special charm that attracts Sakura.
Another possibility is a civilian she has known for a long time in Konoha. Perhaps someone who has always admired her from afar, a merchant who supplies the hospital where she works. He might have shown his love and support for her over the years, and finally, Sakura realizes her feelings for him and decides to marry him.
Maybe she kisses one of her rivals in a competition. This could be a way to throw the rival off - guard or perhaps it's a moment of sudden understanding between them that leads to the kiss. For instance, if they are in a magical competition and Sakura realizes that the rival has a side to them that she never noticed before, and in a moment of impulse, she kisses them.
Maybe it's a powerful noblewoman from within the Seven Kingdoms. A woman who has been overlooked for marriage before but has her own influence and resources. Her marriage to Robert could be a way for her to gain more power and for Robert to gain more support within his own realm.
One possible plot twist could be that the person Sakura is marrying is actually under a spell. For example, an enemy might have cast a love spell on him to get close to Sakura for some devious plan. Another could be that Sakura discovers at the last minute that the man she's about to marry has a hidden identity. Maybe he's a long - lost relative of an enemy she thought she had defeated. It would add a lot of drama to the story.
Maybe the fanfic could be set in a post - war world. Sakura is tired of the constant fighting and death. She then encounters a kind - hearted artist. He shows her a different side of life, full of beauty and creativity. Their relationship develops slowly. However, Sasuke or Naruto might have some issues with her choice at first. But in the end, she follows her heart and marries the artist. The story could also include how she uses her ninja skills to protect the new peaceful life she has built with her new husband.
Title: 'Sakura's Unexpected Engagement'. In this fanfic, Sakura could be engaged to a mysterious stranger. Maybe he's a powerful wizard from a far - off land. The story could start with Sakura's friends being shocked at the news. They wonder who this person is and what Sakura sees in him. As the story unfolds, Sakura might start to have doubts about the engagement herself, realizing she may have rushed into things without really knowing her fiancé.
Maybe it could be her long - time rival. This would be really unexpected because they've always been at odds. But perhaps there was some hidden admiration or understanding between them all along that they didn't realize until later. It would completely change the dynamic of their relationship from enmity to love, which would be a very interesting turn of events in the fanfic.
One possible plot could be that Sakura is in an alternate universe where she has lost her memory and kisses someone else thinking they are her true love. Another could be that she is under a spell which makes her kiss someone else, and then she has to deal with the consequences of that action.