无底

jīn kuàng bìng bù shì wú dǐ de bǎo zàng jīn zi zhōng jiū huì bèi cǎi guāng

金矿并不是无底的宝藏，金子终究会被采光。

A gold mine is not a bottomless pit, the gold can run out.

xīn zhōng wú dǐ

心中无底

be not sure about