"您想买什么？"

Translation: What would you like to buy?

[harijoel]

您(nín) = you (courteous, as opposed to informal 你)

您好(nínhǎo) = hello (polite)
您的(nínde) = your, yours (polite form)

[Imnuts7]

Unlike the T-V distinction in European languages, you can use 您 when addressing your grandparents to convey filial piety/respect for the elderly （孝）.

[_LolZ_]

Yes, similar to tú and usted in Spanish

[MakaiPost]

But unlike Spanish, it doesn't change the grammar for the rest of the sentence.

[1mrunninG]

¡Gracias!

[FaizalZahid]

Xiexienin

[Agnes278593]

Thank you

[pierobonal]

Interesting, this is is the same of lei in italian, usted in Spanish and vous in French. (You sir in English ?)

[Tydal.]

Actually "you" is the formal way of adressing someone in English. Thee, thou, thy, thine used to be the informal way. But since English dropped the informal way, the formal way became the informal way.
Doesn't make a lot of sense, but what actually does in English?

[sadfhrw]

And since 'thee, thou...' stuck in the Bible, it now sounds much more formal and consequential than the everyday 'you'.

[duckmaestro]

What about "Would you like to buy something?"

[JensBjrnha1]

That would be a yes/no question, and there is no 吗 or the like.

[_LolZ_]

"Would you like" is the same as "Do/Would you want" I think

[Haruki_2000]

That would be ”你想买东西吗？“

[Andrew-Lin]

您想買什麼？