Rosa was the daughter of the trader Samuel Tobias and his second wife Sophie Isaak, born in Recklinghausen on July 24, 1904. Rosa married Karl Jacobs from Haselünne, Emsland. Their daughter Ingeborg was born in June 1926 and son Kurt Wolfgang in September 1928 in Recklinghausen. In October 1935, the family emigrated to Heerlen, Netherlands, where their daughter Ursula was born on January 1, 1938. In June 1942, they lived in Maastricht. On August 31, 1942, the whole family was murdered at Auschwitz.
Also her brother Erich Tobias had fled to the Netherlands and was deported as well as her nephew Walter Baroch and his family. Two siblings, two maternal half-siblings and two paternal half-siblings were deported from Germany. Three paternal half-siblings managed to emigrate from Germany to Argentina and the United States. Her mother Sophie Isaak is said to be emigrated to the Netherlands in 1939 but we have no information on her whereabouts.