More info about the name "Erna"
Erna is a German variant of Ernestine. Ernestine originates in Germanic languages and means "serious and earnest woman". It is a feminine form of Ernest, the name which was popularized by Oscar Wilde in his play The Importance of Being Earnest. As a feminine given name, Ernestine became very rare in the United States and nowadays is considered rather old-fashioned.