用微笑假装自己不悲伤
[yòng wēi xiào jiă zhuāng zì jĭ bù bēi shāng]
Translating '用微笑假装自己不悲伤' gives us 'Pretending Not To Be Sad With A Smile', which conveys using smiles as camouflage against sadness or despair - possibly masking vulnerability in fear of displaying true emotions.