笑容掩饰虚伪

'The smile hides the hypocrisy' conveys the message that while presenting oneself cheerfully on the outside, there may be some hidden dissatisfaction or even insincerity underneath. People using such a nickname might have had painful memories or difficulties expressing their true feelings openly. Thus, smiling sometimes serves as a means of protecting oneself from further getting hurt or revealing vulnerability to others, especially in certain social situations.