强颜欢笑并不代表快乐伤心落泪并不代表懦弱
[qiáng yán huān xiào bìng bù dài biăo kuài lè shāng xīn luò lèi bìng bù dài biăo nuò ruò]
It means 'forced laughter does not necessarily mean happiness; tears of sorrow do not necessarily represent weakness.' This phrase reflects complex emotions—people can hide true feelings behind expressions.