A sure thing comes once in a lifetime... but the real thing lasts forever.

The Sure Thing (1985)

Directed by Rob Reiner

Gib, a beer-guzzling slob, and Alison, an uptight Ivy-Leaguer, are an unlikely duo stuck together on a cross-country trip during Christmas break. At first they get on each other's nerves but, as time passes, they find their divergent natures complement each other. Now they need to realize what they've already found before it's too late.