Derwin

Derwin (and Darwin) could be considered a modern English form of the Old English feminine name "Deorwynn" [in the Submitted Names Database] meaning "beloved (or dearest) joy".
(Source: https://anglisc.miraheze.org/wiki/Anglish_Given_Names)

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Derwin could be Latinized to become "Derwina" or "Derwinna". Based on endings of other Old English feminine names ending in -wynn (like -wyn, -wynne, -wen, -wena and -wenna), I imagine that Derwynn, Derwyn, Derwynne, Derwen, Derwena and Derwenna could work as other forms. Unfortunately I can't find sources showing these though.

Darwen and Darwent are other masculine forms as well. (Source: https://www.surnamedb.com/Surname/Derwin)