nín

you (courteous, as opposed to informal 你[ni3])

you (你) + heart (心) = respectful you

To address someone with 您, you extend not just the word 'you' but also your heart toward them. The added 心 signals deference and warmth, marking this as a respectful register.

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The informal second-person pronoun 'you'Semantic
HeartSemantic

Words with 您

您好

nín hǎo

hello (polite)