Learn Danish: Hvis man hviler sig, forbedrer det ens mentale velvære. - If one rests, it improves one's mental well-being.

ens is the possessive form of the impersonal pronoun man (meaning "one's"). We cannot use the reflexive possessive sin here because the subject of the main clause is det ("it"), not man. Because sin only refers back to the subject of its own clause, we must use the regular possessive ens to refer back to the "one" from the first clause.

Why does man take the pronoun sig in hviler sig?

The verb at hvile sig (to rest) is reflexive in Danish, meaning you literally "rest yourself". The impersonal pronoun man is treated grammatically as a third-person singular word (like he, she, or it), so it uses the third-person reflexive pronoun sig.

Why is the word order forbedrer det instead of det forbedrer?

This happens because of the Danish V2 (verb-second) rule. The entire subordinate clause Hvis man hviler sig acts as the first block of information in the sentence. The main verb forbedrer must immediately follow it in the second position, which pushes the subject det into the third position.

Why does the adjective mentale end in an -e?