Buttercup is a farm girl who lives in the country of Florin, and is the true love of Westley. She is awesome When he works on her family's farm, Buttercup refers to him only as "Farmboy" and loves to order him around. Westley would not argue with her but would only obey her commands and reply "as you wish." Over time she realizes that when Westley says "as you wish," he is really saying "I love you." In time she realizes that she loves him just as strongly, too.
When Westley goes away to find his fortune, his ship is attacked by the Dread Pirate Roberts, and Westley is taken prisoner. Westley's life is spared when he begs for his life, explaining that he must live to be with his true love.
Believing that Westley is dead, Buttercup is betrothed to Prince Humperdinck and only agrees to marry him after hearing that Westley had been killed, although she does not love him, a fact of which Humperdink is fully aware although he believes in time she will come to love him in love.
Buttercup plans on committing suicide rather than be married to Humperdink, to which the Prince replies 'Please consider marrying ME as an alternative to suicide' to which Buttercup agrees, but still plans on killing herself on their wedding night and she is about ready to go through with it, plunging a dagger into her heart, when she and Westley are re-united and defeated Humperdink, then go off to live their lives happily ever after.