Well, it could be that Sakura finally decides she's had enough of Sasuke's brooding and cold behavior. Maybe she stands up to him about his disregard for the village or his lack of communication with her. She might tell him that she's her own person and won't tolerate his dismissive attitude anymore.
In this fanfiction, Sakura might stand up to Sasuke regarding his relationship with Naruto. Sasuke has had a complex relationship with Naruto, and Sakura could feel that Sasuke is not treating Naruto fairly. She could assert herself, reminding Sasuke of all the times Naruto has been there for him. Sakura's standing up could be a way to bridge the gap between the two friends and also show her own growth and independence.
Sakura would likely become more confident. Standing up to Sasuke means she's no longer the meek girl who just follows him around. She'll start to trust her own judgment more.
In this fanfiction, Peter might stand up to Flash by using his intelligence. For example, if Flash tries to humiliate Peter in class, Peter could outwit him with his knowledge, showing that he's not someone to be pushed around. He could also gain the respect of his classmates in the process, which would be a big blow to Flash's ego.
It could be that Jasper gets into trouble with another vampire clan. Bella, being the kind - hearted and brave character she is, stands up for him. She might use her unique position in the vampire - human - werewolf triangle to negotiate or fight on Jasper's behalf. This could lead to a series of adventures where they have to face various challenges together and strengthen their relationship as a result.
Maybe Sasuke says something really offensive about their past or her skills, and Sakura just snaps and starts beating him up.
One possible reason could be a misunderstanding. Maybe Sasuke has been misled to think Sakura is a threat to him or his goals at that moment. In the Naruto universe, Sasuke has often been on a solitary path filled with suspicion. He might tie her up to keep her from interfering with something he's about to do. Another aspect could be related to some kind of test. He may want to see how Sakura will react in such a difficult situation to gauge her growth as a ninja. It could also be a part of a plan to protect her from something more dangerous, by restraining her movement in a way that he believes is the best for her safety, using the snakes as a means to immobilize her as he is known for his snake - like jutsu.
Sakura might grow tired of Sasuke's cold and distant behavior. In fanfiction, she could realize that she's been trying too hard to hold on to a relationship where she's not getting the love and attention she deserves. Maybe she meets someone else who shows her more care and respect, which makes her consider breaking up with Sasuke.
In fanfiction, Sasuke could start by giving Sakura a sincere apology. He might bring her rare flowers from his travels, as Sakura loves nature. Maybe he could also take her on a special mission where they can work together closely and he can show his trust in her abilities.
One possible plot could be that Sasuke gets injured during a mission and is brought to the hospital where Sakura works. Sakura then uses her medical skills to treat him, and during his recovery, they have deep conversations that rekindle their old feelings for each other.
Maybe Sasuke has been secretly planning the proposal for a long time. He starts by taking Sakura on a journey to different places they've been to in their past adventures. Along the way, he drops little hints. When they reach a beautiful, secluded spot by a waterfall, he gets down on one knee. He tells Sakura that she is the only one who has truly understood him and that he wants to spend the rest of his life with her. Sakura is shocked but then hugs him tightly and accepts.
Well, the plot could be that Sasuke has been away on a long mission. When he comes back, he sees Sakura has become very close to Naruto in a different way. Sasuke starts to feel this twinge of jealousy because he realizes he might have lost his chance with Sakura. He then has to decide whether to confront his feelings or keep them buried.