Throughout The Princess Bride, Buttercup (Robin Wright) and Westley (Cary Elwes) have plenty of kisses — probably. It's just that the audience never gets to see them. The grandson being told their story (Fred Savage) is totally not into hearing about the kissing scenes, which he tells his grandfather (Peter Falk), who is reading to him while he's sick in bed. So Westley and Buttercup might have had a pretty epic first kiss earlier in the film, but we'll never actually know.
Finally, at the end of the movie, Buttercup and Westley are reunited and ride off into the sunset. The grandson has been so moved by their tale of love (and perhaps also by all of the swashbuckling, murdering, and pirates) that he allows his grandfather to keep reading. Thus, we finally get to see Buttercup and Westley engage in an unforgettable kiss. The grandfather's narration puts it perfectly: "Since the invention of the kiss, there have been five kisses that were rated the most passionate, the most pure. This one left them all behind."
