Out of all of the characters, she is the only one Barney chooses to confide in when he realizes that he is in love with Robin. In the fifth season, Lily forces Robin and Barney to confess to being a couple. She does this by detaching the doorknob of Robin's room at the apartment and waits for them to have "the talk". Robin and Barney pass a few notes under the door with vague explanations, none of which satisfy her. To convince Lily to let them out, they lie about being boyfriend and girlfriend, but after they leave the apartment hand-in-hand, Lily tells Ted "they didn't realize they weren't lying."