It is interesting to notice that so many stories, despite some variation in the plot, use similar examples when trying to prove a point. In this case, two stories that have done this are the 1949 film The Heiress, directed by William Wyler and based on Henry James's 1880 Washington Square, and the 1995 movie CutThroat Island, directed by Rennie Harlin. Each movie gave an example of how men take advantage of wealthy, unattractive women whom they first meet at a dance in order to gain their respective fortunes. Surprisingly, the men in each of these movies used the same method.
In the movie The Heiress the director tried to hide Morris' intentions in the beginning, showing instead a man, as played by Montgomery Clift, who was charming to the rich heiress, Catherine, played by Olivia de Havilland. The problem with this situation, which caused the viewer, like the good Doctor Sloper (Ralph Richardson) to become suspicious, was the fact that Catherine was considered boring and unattractive. Therefore, why would a man like Morris, who was poor, be interested in the first place?
The same applies to the woman in CutThroat Island who was also approached while at a dance, as Catherine had been, and charmed by the attention. The only difference was the man, named Shaw, pretended to be a doctor. Later in the scene, it is apparent he had used the woman to steal her jewels by distracting them with flattery. Sure enough, he was found out, and as a consequence he was caught and sold as a slave.
Unless most people spend their whole life in suspicion, most enjoy getting attention. Therefore, Catherine was not naive but blind to Morris's real intent. Often when people, like Catherine or the woman in CutThroat Island, do not get the praise or worthy attention from their friends and family, it is natural to want to accept it from others, even unscrupulous ones with ulterior motives, which they often suspect. In view of that, this concept is easily believable when used in books and films.