So this is what I have found thus far. I don't pay much mind to the U.S. records of people who immigrated because I don't know if that is the person's birth name.
It may be a creation out of Darling, but it seems to have an older use than the 20th century.
But what is Hungarian
Darlene's origin?
British Records (all female)
Derlen (1551)
Direlyne (1588)
Dearling (1624)
Doroline (1629)
Darlin (1680)
Darling (1680)
Dearlin (1798)
Durlin (1788)
US Records (all female)
Darline (1769)
Darling (1733 (it appears a middle name) 1780 appears as a first name numerous times)
Darlin (1788)
Darlene (1791, 1799, 1804)
Daralin (1800)
Derlina (1809)
Doraline (1809)
Dorlin (1782 & 1799)
Durlin (1808)
1 male Darling from 1747
Canadian Record
Derlina (1794)
Hungary
Darielem (1738, 1749)
Darlene (1752 and 1789)
Dérlen (1788)
Darling (1795)
Denmark
Tarline (1755)
FranceDarlhine (1748)
Immigrants to the U.S.
Darlin (b. in
Ireland 1809, census date 1870)
Darlene (date of immigration 1848, from Linfu (don't know where that is) dob 1809)
Darlene (b. in 1809 in Bavaria, census date 1870)