A Modern Cinderella(1917)

Joyce's mother keeps her younger daughter in the background so that Polly, the elder daughter, can monopolize all the eligible young men, especially Tom. Although Tom is Polly's choice, she decides to pique his interest by flirting with Harry. Joyce, who likes Tom herself, decides to defeat her sister's plan by having Tom pretend that he likes her. Soon, the pretense turns to love and Tom proposes to Joyce. To test his sincerity, Joyce jumps into shark-infested waters and almost loses her life. Tom visits her constantly in the hospital and finds that his operation on her heart was quite successful.