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In Asian countries, such as China and Korea, populace's aesthetic is quite different from the US.

We prefer a girl who is more sweet, pure, and inoffensive, (my translation is not authentic in English, since sweet can be used to describe any kind of attractive females). And in Asian countries, it is a praise for a girl if she has the characteristics above. I am just wondering whether there are commendatory and exact words in English to describe such girls (not the word to describe their lack of sex experience).

You can say that she is demure, meaning she is :

reserved, modest, and shy

Oxford Dictionary of English

ladylike from the Cambridge English Dictionary:

graceful, polite, and behaving in a way that is thought to be socially
acceptable for a woman:

For year after year women put forward the demand for enfranchisement
in gentle, ladylike, mild terms.

Some -- perhaps many -- young women in the US nowadays would be irritated at being called ladylike, because, as the example sentence quoted shows, it implies being mild and therefore unforceful and so probably unsuccessful, and also most likely no fun. Paradoxically, the same young women might be defensive if called unladylike because that word implies being rude and crude and unattractive because of her behavior.

Just yesterday I was watching that old but hilarious American TV sitcom Full House. And in the episode I was watching a girl did something unselfish and then was called a kind and fair princess. The adjectives in bold may be simple but I'm sure they express your idea.

decorous vocabulary.com adj

characterized by propriety and dignity and good taste in manners and
conduct

As in:

She is a decent and decorous woman.