放心 is really commonly used to mean not to worry about something, or simply just trust, or “I got your back.”  The words literally mean to put your heart at ease.  Here is an example dialogue using this phrase 放心 Fàngxīn don’t worry 有什么不放心的，周末把孩子交给奶奶爷爷，你去工作加班吧 Yǒu shé me bù fàngxīn de, zhōumò bǎ hái zǐ jiāo […]