S04E15 - I Love Lisa
On Valentine's Day in Springfield, Lisa's class at the Springfield Elementary School construction paper mailboxes for the Valentine cards they are about to receive. When Ralph does not get any cards and breaks down in tears, Lisa hastily gives him a card out of sympathy. Ralph immediately cheers up, and develops a romantic interest in her. Ralph begins to annoy Lisa at every turn. Lisa tries to escape the situation by telling Ralph she is not ready to be romantic, but Ralph uses his position as Chief Wiggum's son to get her tickets to Krusty the Clown's upcoming 29th Anniversary Special, as well as a leading part for himself in a President's Day pageant in which Lisa also stars. Ralph receives the role of George Washington opposite Lisa as Martha Washington.
With Homer having convinced Lisa that nothing can go wrong at Krusty's show, Lisa and Ralph go together. On live air, Krusty begins interviewing audience members, and Ralph takes the opportunity to declare that Lisa is the love of his life and that he intends to marry her in the future. Angry, Lisa snaps, stating that she had never liked him and that the only reason she gave him a Valentine was because nobody else would. Later at home, Bart takes the moment to replay that scene to Lisa in which Ralph is humiliated and deeply hurt. Lisa soon feels guilty and regrets her actions in hurting Ralph's feelings.
On the night of the Presidents' Day pageant, Lisa tries to apologize to Ralph, but he ignores her to focus on his role. Ralph proves to be a remarkably effective and eloquent actor, gaining the approval of the audience. Lisa approaches Ralph after the performance and apologizes for her actions. He accepts and she gives him a new card with a picture of a bee on it, reading "Let's 'Bee' Friends". Ralph laughs at the pun and happily accepts the offer of friendship.