人心对人心四两换半斤
[rén xīn duì rén xīn sì liăng huàn bàn jīn]
A phrase indicating fair trade or honest exchanges. Implies mutual trust and fairness are fundamental in social interactions, suggesting people should treat others with equivalent sincerity. A cultural metaphor derived from traditional Chinese weighing system, where exchanging four ounces for eight ounces represents balanced, equal dealings.