人心莫测人心险恶
[rén xīn mò cè rén xīn xiăn è]
Acknowledging unpredictability and malevolence within human relationships, this implies that intentions behind social bonds aren't always benign and may contain concealed agendas. People can behave unpredictably or even deceitfully, reminding us always to remain cautiously aware of the complexity inherent in interpersonal dynamics.