Young at Heart (1954)

When Alex enters the lives of the musical Tuttle family, all three daughters fall for him. He is charming, good-looking, and personable. Laurie and Alex seem to be made for each other, and they become engaged. When Barney comes into the picture to help Alex with some musical arrangements, matters become complicated. Laurie sees him as a challenge; she can't believe anyone could be as cynical as he is, and she is more than a match for his gloomy outlook on life.