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Jyutping zan1 zyu1 dou1 mou5 gam3 zan1
Pinyin zhēn zhū dōu mǎo gàn zhēn

Definitions (Wiktionary)
  1. phrase, Cantonese, idiomatic
    completely true; absolutely real

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Jyutping zan1 zyu1 dou1 mou5 gam3 zan1
Pinyin zhēn zhū dōu mǎo hán zhēn

Definitions (粵典–words.hk)
  1. 語句
    絕對​係​真​;​冇​花​冇​假
    one-hundred-percent true, totally genuine, absolutely real; a wordplay on 珍珠zan1 zyu1 'pearl', the first character of which has the same pronunciation as 真zan1 'real'; literally 'more real than pearls'
Definitions (Kaifangcidian)
  1. 千真萬確 – 千真万确
  2. 非常真實 – 非常真实
  3. 絕對是真的 – 绝对是真的
  4. 真的不能再真

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Jyutping zan1 zyu1 dou1 mou5 gam2 zan1
Pinyin zhēn zhū dōu mǎo gān zhēn

Definitions (CC-CANTO)
  1. completely genuine or real (slang)
Examples (粵典–words.hk)
  1. Cantonese
    珍珠都冇咁真
    珍珠都冇咁真
    zan1 zyu1 dou1 mou5 gam3 zan1
    • one-hundred-percent true; literally: more real than pearls