The Ambassador's Daughter (1956)

Joan Fisk, daughter of the American ambassador to France, is bored with entertaining the wives of visiting V.I.P.s and decides to conduct an experiment. She accepts a date with an American G.I. and tries to prove to her father and his friends that not all soldiers are wolves. But by the end of their first date, after wine, music and the young man's charms have swept her off her feet, she realizes that she may have won more than the bet.