Obviously, Sakura is one of the main characters. As for the enemy, it could be a character who has been opposing Sakura's side in the original story. It might be someone with a dark past or different motives.
Perhaps Sakura is forced to sleep near the enemy's territory due to some strange circumstances in the story. As she sleeps, she has strange dreams that are somehow connected to the enemy's past. This leads to her waking up with a new perspective on the enemy and tries to communicate with them to figure out the mystery behind those dreams.
The true story behind 'Sleeping with the Enemy' is a harrowing tale. A woman is trapped in a marriage filled with domestic violence. Her husband is manipulative and physically abusive. She devises a clever plan to get away. She stages her death and flees to a different town. There, she begins to heal and regain her sense of self. But her husband is not one to give up easily, and the story is filled with tension as she tries to keep her new life a secret while fearing his discovery all the time.
I'm not entirely sure as I haven't read the novel in detail. But usually, there would be a protagonist who is in the situation of'sleeping with the enemy' and then the character who represents the 'enemy' figure.
The main theme is often about the complex relationship between the protagonist and the so - called 'enemy'. It might involve themes of trust, betrayal, and the discovery of hidden identities.
Sakura can be developed by showing her initial fear and hesitation when she first has to sleep with the villains. As time goes on, she could start to show her strength and resilience, not letting the situation break her. For example, she might start to give the villains some moral lessons during their interactions while in that sleeping situation.
In this kind of fanfiction, Sakura might be in a very dangerous situation. She could be facing Itachi's powerful jutsu while struggling in his grip. Itachi is a very strong character, so Sakura may have to use all her skills and knowledge just to survive. Maybe she'll try to break free and find a way to counter Itachi's moves.