没心没肺的笑无声无息的哭
[méi xīn méi fèi de xiào wú shēng wú xī de kū]
Translates into 'Heartless laugh and soundless cry'. It conveys extreme emotional contrast between outward happiness (a laugh devoid of true emotion) and inward pain (silent crying), suggesting a complex inner turmoil despite appearing fine on the surface.