Rosamund is Robert's sister and she lives alone in a house on Eaton Square in Belgravia, London, which was bought by her late husband Marmaduke Painswick immediately after their wedding. They had no children and her mother Violet looks down on Marmaduke, who was a wealthy banker. Rosamund is one of the more headstrong and outspoken members of the family. She is devoted to Robert and his family and thus feels it is her duty to speak her mind on every possible occasion, though her interference in her nieces' decisions has disastrous results.