Rosette Koster worked in October 1941 as a seamstress with the lingerie- and ready-made clothing company SIDVA (Simon de Vries Ateliers) in Amsterdam. She then had been in office for four years. At that time she was not married yet.
Lijst van Joodsch Personeel-SIDVA Oct. '41
April 1942 Rosette Koster married496126.
City Archive of Amsterdam, card Rosette Koster
This person is commemorated on a memorial in Vierhouten. More information on this memorial can be found (in Dutch) on the website of the Nationaal Comité 4 en 5 mei.