She would definitely change. Sakura might become more serious and less of the bubbly girl she used to be. She would remember Naruto's sacrifice every day and use it as a driving force. She could also start to see the world in a different light, realizing the true cost of the ninja life and the importance of protecting those you love. She may become more involved in the political aspects of the village to ensure such a tragedy doesn't happen again.
Sakura would likely be filled with a mix of emotions. On one hand, she'd be heartbroken, but on the other, she'd be angry at the situation and the ones who put Naruto in a position where he had to sacrifice himself. She could start training obsessively to become strong enough to avenge Naruto.
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.
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.
Naruto might also try to remember Sakura in a positive way. He would cherish the memories they had together. He could start initiatives in the village in her name, like promoting medical ninja training more, since Sakura was a great medical ninja. He would slowly turn his grief into a force for good in the village.
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 would be devastated. He's always been one to value his friends deeply. He might initially go into denial and then be filled with rage, vowing to find out who or what was responsible for her death and seek justice. He would also likely carry a great deal of guilt, thinking that he should have been able to prevent it.
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.
One possible plot development could be that Sakura is deeply affected by Naruto's sacrifice. She might vow to carry on his will and become even stronger. In the story, she could use Naruto's death as motivation to finally achieve peace in the ninja world. For example, she could take on Naruto's dream of uniting all the villages and work towards it with all her might.
Sasuke would be deeply affected. He and Naruto had a complex relationship. He might feel regret for not being there to help Naruto and also feel a new sense of purpose in avenging his friend. Sakura would be heartbroken. She had always cared for Naruto, and his death would make her question the purpose of the ninja life. Haku herself would be in a state of shock and disbelief. She would feel a heavy burden of guilt, knowing that Naruto sacrificed his life for her. She might become more withdrawn initially but then use Naruto's memory as a motivation to become stronger.
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 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.
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.