看破尘世冷暖
[kàn pò chén shì lĕng nuăn]
This implies a person who has gone through many experiences in life ('尘世' meaning 'the secular world'), and has seen through the warmth (friendship, love, etc.) and coldness (deception, harm, abandonment, etc.) of human relations. It portrays someone who remains indifferent and calm faced with all aspects of social reality.