Kertes, Susi.

Susi Kertes was a close family friend of Alma Mahler and Franz Werfel since at least the 1930s; Susi had been a friend of Alma's daughter and Franz's stepdaughter Manon Gropius (1916-1935), according to a reference by Alma in her memoir Mein Leben. Harald Tauber was Susi's husband. Susi and Harald were both actors at the time of the correspondence.

From the description of Correspondence to Alma Mahler, 1940-1948. (University of Pennsylvania Library). WorldCat record id: 155863639