S1·E88 Ran-chan's Great Date Plan!

Admiring Ran's feminine beauty, Ryunosuke goes out with her in an attempt to become more feminine, but everyone else except Ran (who doesn't know Ryunosuke's true gender and thinks she's going on a date with a guy) thinks this means she's interested in girls when she claims she has no interest in boys. Lum and Ataru decide to intervene with Ran and Ryunosuke's "date".