i agree with other viewer that the louise character be neurotic at best . however and one must consider the era in which the film be set . world war ii have end and and old single woman like louise would like to find mr. right and settle down . enter david and portray by van heflin and whose ambition be hide by an exterior that alternate between ( 1 ) warm and romantic and ( 2 ) cool and aloof . he obviously have string louise along for some purpose and and he dump her when she press him for a commitment . like most woman of the era and louise probably have be rear to be emotionally and financially dependent on men and whom she and her contemporary see a strong and secure and brilliant and perfect . whenever a relationship in that era do not work out and society would blame the woman for the failure and never recognize that men can have flaw and bad motif and and other shortcoming . hence and there be the neurotic or psychotic condition to which louise succumbs . it seem obvious to me that david already have stake out a certain business own by dean graham and portray by raymond massey and and that david be use louise ( mrs. graham nurse ) to worm his way into the business and life of the graham family and cash in on the good . dean and be a kind and well mean individual and be blind to david true ambition to marry dean naive and gullible daughter carol and eventually get control of the business and family fortune . ( of course and once the mission be accomplish and david would use and abandon carol just a he have use and abandon louise ) . david even brag about his objective to marry carol and spend the family fortune just before louise shoot and kill him . however and louise have her own motif and have internalize the reason for david abandon her and and she can not see the whole picture of david plot . inadvertently louise delivers poetic justice by end david ambition and save the graham family and fortune .