the human heart is a mystery
The Chinese idiom, Pinyin is R é nx ī nm ò C è, which means that people's hearts are hard to detect. From Zhang cangshui's epitaph
The origin of Idioms
In the epitaph of Zhang cangshui written by Huang Zongxi in Qing Dynasty, it is said that "only by this line of undead people's heart, we think it is surging, but the situation is clear, and the people's mind is unpredictable."
Idiom usage
As a predicate or attributive; used in people's mind.
the human heart is a mystery
arranged in a crisscross pattern - zòng héng jiāo cuò