Born Giusta Manca di Villahermosa in Milan, she belonged to an aristocratic family from the Sardinian town of Sassari.

[1][2] After a bit part in the Camillo Mastrocinque's film Regina della Scala, in which she basically played herself, Manca di Villahermosa decided to start a career as an actress and she adopted the stage name Rubi Dalma (sometimes spelled as Rubi D'Alma or Ruby Dalma).

[1] Her breakout role was as the aristocrat donna Paola unsuccessfully courted by Vittorio De Sica in Mario Camerini's Il signor Max.

[1][2] From then Dalma started a successful career, even if often limited to stereotyped roles of cold, sophisticated and sometimes snobbish noblewomen.

[1] After the war she mainly appeared in character roles and, gradually, moved away from the cinema industry.