脸上有笑是因为心里太无奈
[liăn shàng yŏu xiào shì yīn wéi xīn lĭ tài wú nài]
The phrase 'smiling on the outside due to internal helplessness' portrays putting on a facade despite inner frustrations. Suggesting masking true feelings behind smiles, possibly revealing a coping mechanism amidst emotional difficulties or resignation towards circumstances.