黑夜再黑也不及人心黑寒冰再寒也不及人心寒
[hēi yè zài hēi yĕ bù jí rén xīn hēi hán bīng zài hán yĕ bù jí rén xīn hán]
Even the darkest night cannot match the darkness within human heart. Even ice as cold cannot reach the cold in people’s heart either. This suggests profound sadness about human nature.