xīn心heartxīn心heartxiāng相mutuallyyìn印imprint
Hearts imprinted on each other — in perfect mutual understanding.
Literal meaning
heart (心) — heart (心) — mutually (相) — imprint (印)
Origin
Originally a Chan (Zen) Buddhist phrase about the direct transmission of understanding from master to disciple, mind-to-mind, without need for words (以心传心，以心印心). Modern usage broadened the phrase beyond Buddhism into describing any pair — lovers, close friends, long-married couples — whose understanding of each other doesn't need to be spoken.
Examples
Tā他men们liǎ俩xīn心xīn心xiāng相yìn印，bú不yòng用shuō说huà话jiù就dǒng懂duì对fāng方。
Those two are in perfect accord — they understand each other without speaking.
Zhēn真zhèng正de的péng朋yǒu友，xīn心xīn心xiāng相yìn印。
Real friends share an unspoken understanding.
Usage & nuances
Warm, intimate register. Works for romantic partners, very close friends, or sometimes between a teacher and a star student. Slightly poetic — feels deliberate when you use it.
Learn idioms by speaking them
Idioms are most useful when they land in a real conversation. Practice them out loud in Kango — get instant feedback on tone and timing.
Download Kango on iOS