Fools Rush In (1996)

Two relative strangers try to turn a one night stand into a marriage in this romantic comedy. Alex Whitman (Matthew Perry) is a designer from New York City who is sent to Las Vegas to supervise the construction of a nightclub that his firm has been hired to build. Alex is a straight-laced WASP-ish type who, while enjoying a night on the town, meets Isabel Fuentes (Salma Hayek), a free-spirited Mexican-American photographer. Alex and Isabel are overtaken by lust at first sight and end up spending the night together; however, their immediate attraction doesn't last in the cold light of day, and they don't see each other for another three months. When they do meet again, it's because Isabel has some interesting news for Alex: she's pregnant with his child.