I now remember the movie (title) Donovan's Reef but can't remember anything about the movie as I was so young then....just that it's about deep sea divers. John Wayne was my favorite actor when I was a kid.
The film is gentle, deliberate in pace and pits
two screwball comedy types,

the seemingly over-macho but lovable brute and the seemingly stuck-up by basically-goodhearted girl against one another; and from the beginning as his steely spirit and her iron resolve meet sharply , sparks fly. In the film's focused storyline, a youthful, would-be heiress from Boston, Ameiia (Elizabeth Allen), travels from her cold, snowy and overly-formal zone of existence to locate her father, missing since WWII. She had been born near the beginning of that Pacific conflict; but he stayed in French Polynesia and has never seen her. He stands to inherit millions, that is the prospect; she needs to prove that he is "morally unfit" in order to overturn that provision of a will. The assumption is he must be living in sin, he's in paradise--not Boston.
She is met not by her errant papa but by his friend, "Guns" Donovan (John Wayne), an ex-sailor, and a man who who owns the local saloon, 'Donovan's Reef'. What she does not know is the father (Jack Warden) has had three children since, by a Polynesian mother. It takes time, a brawl over a shared birthday, meeting and growing to love the people, some tense scenes with her father, ceremonies, arguments, a water-skiing contretemps involving two sorts of bathing suit representing Boston and Polynesia and an opportunistic play for her by the governor that the girl finally melts--in so far as iron can. She decides it is more logical to stay with Donovan than to deny her feelings, and her love for the island. Donovan spanks her, the Amelia that was; but the action is symbolic, for from this point on they will be equals,; his brawling partner (Lee Marvin) will own 'Gilhooley's Reef' and and they will make a life together where people get along and respect one another's differences.
John Ford is never far from cavalry-post humor, and the build of the romance from a hotly-denied spark through incidents, misassumptions, mutual interactions and learnings prepares us not for surrender but for a warlike alliance at the end; and for a procession of priests, friends, children, Gilhooley, her father, and a huge French policeman bearing her worldly goods to Donovan's house in train behind the happy couple.
Cast members;
John Wayne ... Michael Patrick 'Guns' Donovan
Lee Marvin ... Thomas Aloysius 'Boats' Gilhooley
Elizabeth Allen ... Ameilia Sarah Dedham
Jack Warden ... Dr. William Dedham
Cesar Romero ... Marquis Andre de Lage
Dick Foran ... Australian Navy Officer
Dorothy Lamour ... Miss Lafleur