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While some might read Sasuke's calm demeanor as uncaring, it's exactly the opposite. Anyone familiar with the Uchiha clanwill notice that several of the clan members have the "skill" of remaining expressionless in order to hide their true emotions, which is essentially a protective mechanism. So long as others can't read their emotions, they can't use those feelings against them. Sasuke mastered the ability of remaining expressionless and keeping his emotions concealed back when he was a teenager, frequently keeping his emotions hidden and under wraps in Shippuden. In Boruto, Sasuke is generally more expressive and doesn't hide his emotions quite so much. However, after Sakura is captured, we see Sasuke close himself off once again, behaving coldly with a detached aura. I see this as an indicator of him caring immensely, not being uncaring. Sasuke is distressed enough by his wife's capture that he is calming himself down by resorting to his habitual protective mechanism he used as a teenager (and still sometimes uses as an adult, apparently): projecting an aloof, uncaring aura externally and suppressing his true feelings in order to prevent his anxiety leading to panic. In addition to keeping himself calm so as not to lose focus and make sloppy mistakes, Sasuke has two children in tow to think about: Sarada and Chocho. Sasuke hates when people panic, so the last thing he wants is for his anxiety to add to Sarada's own worry (emotions are contagious, and openly worrying about Sakura is likely to make Sarada's fear worse).
Despite his pretense of not being too concerned about Sakura's capture, there are hints cuing us readers in to the fact that Sasuke is a lot more worried than he outwardly lets on.
Firstly, Sarada challenges Sasuke how he can act so calm when his wife had been captured by the enemy. Naruto tellingly tries to step in to explain Sasuke's behavior. As Sasuke's closest friend, Naruto knows Sasuke a lot better than Sarada does and knows that Sasuke processes and exhibits emotions differently than your average person; Naruto knows Sasuke cares about Sakura but that he isn't one to wear his heart on his sleeve. Thus why Naruto is completely unbothered by Sasuke's outwardly cold demeanor, seeing as how Naruto doesn't look displeased in the slightest by Sasuke's behavior. In fact Naruto even attempts to defend Sasuke from Sarada questioning his emotions by stepping in to explain Sasuke's behavior.
Sasuke's blunt reply to Sarada's confrontation is "personal feelings don't matter". Sasuke never said he isn't worried about Sakura, but he doesn't believe that such emotions are constructive, helpful, or relevant to the job of rescuing his wife. He's trying to teach his daughter that allowing emotions to control you will only lead to irrational, foolish decisions, and feelings aren't the best for thinking logically and calmly and practically. Panicking won't do Sakura a bit of good.
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