Betje Zwarts was a daughter of Abraham Zwarts and Sara Wertheijm. She married Simon van Bever in Amsterdam on 6 February 1935, a son of Samson van Bever en Sientje Smeer. They had had three children together: Samson, Sara and Sientje. Betje and her three children have been killed in Sobibor on 9 July 1943. Her husband Simon van Bever lost his life already in Mauthausen on 1 September 1941.
City Archive of Amsterdam, archive card of Samson van Bever, Simon van Bever and Betje Zwarts.