Hostess is the same as Hostess Quickly of Henry IV, Part Two. Despite having become engaged to Nim, she has recently married Pistol.
She attends Falstaff in his last hours, trying to keep him comfortable. She is not overly happy to see all her men go off to war, but lets them. Her foolishness (see Henry IV) seems to have vanished in the wake of Falstaff’s death and the start of the war: though she still misuses language, she is a much quieter woman. Riddled with venereal disease, she is killed by them while Pistol is in France.