Ultimo metrò (1999)

A young man enters the Rome Metro with a friend, where they notice a woman who has just left the restroom with her dress accidentally tucked into her panties. They tell her about her inadvertent exposure, after which one of the boys boards a train, leaving his besotted friend standing on the platform - totally smitten with the lovely young lady. The two are waiting on opposite platforms, where they await the last train. The young man proclaims his love at first sight - telling her she's the most beautiful woman he's ever seen. Obviously flattered, the woman reciprocates in a way the young man will never forget...