Collins Chinese Dictionary Plus (3rd edition), 2011:
心心相印 xīn xīn xiāng yìn be a kindred spirit
- 她希望找一位心心相印的伴侣(侶)。 Tā xīwàng zhǎo yī wèi xīn xīn xiāng yìn de bànlǚ. She hopes to find a partner who is a kindred spirit.