Sakura may react with a sense of urgency. She would drop whatever she was doing and rush to Naruto's side. She'd be worried that something truly terrible has happened. If Naruto is hesitant to talk, Sakura might just sit quietly with him, waiting for him to open up. This would show her patience and understanding, and also how much she values Naruto as a friend.
Sakura might be completely shocked at first. She might freeze for a moment, not believing what's happening. Then she could start crying tears of joy and say yes immediately.
Naruto's reaction could be complex. Since he has his own feelings for Sakura, this situation could stir up a lot inside him. He might initially be a bit hesitant in how to approach her because he doesn't want to overstep any boundaries. But in the end, his natural instinct to help a friend would take over. He would listen attentively to Sakura, his eyes full of determination to make her feel better, and use his own unique way of thinking to give her advice or just be a shoulder to cry on.
Sakura would be devastated. She would probably blame herself for Naruto's death since he died protecting her. She might go into a state of deep depression at first, withdrawing from everyone.
On the other hand, Sasuke could be very stoic about it on the surface but internally be in turmoil. He might start to analyze his own actions and whether he had missed any signs from Sakura. He could also be the type to immediately start thinking of ways to win Sakura back if he realizes he can't stand the thought of her with someone else.
Sakura might become more empathetic. Seeing Naruto's memories would expose her to his pain and his hopes, so she would be more understanding of his actions and decisions.
Sakura might react by being more assertive around Naruto. Instead of being shy or holding back, she could be more forward in showing her friendship or even her deeper feelings. She may also try to intimidate the fangirls in a way, like using her strength as a ninja to show that she is not one to be trifled with.
Sakura would likely be devastated. Naruto has been her friend and teammate for a long time. His death would leave a huge void in her life, and she'd probably go through a long period of mourning.
Sakura might initially be confused. She would probably wonder why Naruto is acting this way all of a sudden. For example, she might try to get his attention by calling his name a few times, but when he doesn't respond, she could be left feeling a bit bewildered.
At first, Naruto might be really confused. He's used to the normal Sakura, so when she starts acting all yandere, he'd be like 'What's going on, Sakura - chan?'. He'd probably try to talk to her and find out what's wrong.
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.