Qǐchū shì kāi wánxiào, jiéguǒ nòng jiǎ chéng zhēn, tā zhēn de cízhí le.
It started as a joke, but he ended up actually quitting his job — pretense became reality.
Tips
history
Recorded in Song-dynasty poet Shao Yong's 《弄笔吟》(Nòng Bǐ Yín): 弄假像真终是假,将勤补拙总输勤 — 'fake made to look real is still fake.' The idiom inverts the original: sometimes the fake actually does become real.
culture
A favorite romantic-comedy trope in Chinese fiction and TV: fake-dating, fake-marriage and fake-engagement plots that turn into the real thing — 弄假成真 is the standard label for the genre.