fàng xīn
你只管放心，出不了错
Nǐ zhǐguǎn fàngxīn, chū bù liǎo cuò.
Just rest assured, nothing will go wrong.
看到一切都安排好了，他才放了心。
Kàn dào yīqiè dōu ānpái hǎo le, tā cái fàng le xīn.
Only after seeing that everything was arranged did he feel relieved.