Sakura could also try to appeal to Itachi's humanity. She might mention his love for Sasuke or the good that she believes is still in him. She could say 'Think about Sasuke. If you harm me, it will hurt him too.' This way, she is trying to make Itachi see the consequences of his actions and hoping to make him lower the kunai.
Sakura would probably be scared at first. But then, being the strong - willed character she is, she might start to talk back to Itachi. She could say something like 'You don't want to do this, Itachi. I know you have your reasons, but this is wrong.' She would try to use her words to defuse the situation.
She might also try to use her combat skills. Sakura has been trained by Tsunade. So, she could look for an opening to disarm Itachi. Maybe she would feign weakness at first, and when Itachi least expects it, she would try to knock the kunai out of his hand with a swift and precise move. However, she would also be cautious because she knows Itachi's reputation and skills.
Well, one possibility could be that Itachi is under some sort of mind - control. Maybe an enemy has forced him to target Sakura as a way to get to Naruto or the rest of Team 7. He holds the kunai to her throat but is fighting internally against the control, his eyes showing the struggle.
Sakura might initially be terrified. She would probably try to fight back using her combat skills and medical ninjutsu to defend herself. Since she is a strong - willed character, she won't go down without a fight.
Sakura would probably be angry at herself for being captured. She's a proud ninja. So she would start looking for weaknesses in Itachi's hold on her. Maybe she would try to engage him in conversation to find out his motives, all the while formulating a plan to break free. She could also try to send out some sort of signal to her comrades if possible.
Sakura would probably be initially terrified. She would try to use her medical ninjutsu skills to defend herself or at least slow Itachi down. If she realizes she can't overpower him physically, she might try to talk to him, asking him why he's doing this.
She might be a bit confused at first. After all, Itachi has a very complex and somewhat dark past. But she could also grow to understand her father's perspective as she learns more about Itachi herself.
There would be other fans who might be intrigued. They like to explore different 'what - if' scenarios in fanfiction. They would see it as a creative way to explore the characters in a new light, even if it goes against the canon. However, they would also be aware that it's just a fictional alternative and not the real Naruto story.
She might be surprised at first. After all, Naruto isn't known for his singing usually. But then she could be touched if she realizes the song is for her and about their relationship, whether it's friendship or something more.
Sakura would probably be horrified. She knows Orochimaru's reputation for being cruel and power - hungry. She would immediately reject any offer from him and get ready to fight if necessary. After all, she has grown into a strong kunoichi and won't be easily intimidated.
Sakura might be heartbroken at first. She has always been in love with Sasuke and to find out he's cheating would shatter her world. She could become withdrawn and focus more on her medical ninjutsu as a way to cope.
Kakashi, as their sensei, would be disappointed. He would hope that they could resolve their differences maturely. He might offer some advice based on his own experiences in relationships, but ultimately it would be up to Itachi and Sakura to decide whether to take it or not.