捂得住眼捂不住泪瞒得过人瞒不过心
[wŭ dé zhù yăn wŭ bù zhù lèi mán dé guò rén mán bù guò xīn]
'Can Cover Eyes But Not Tears; Can Fool People But Not the Heart'. Indicates that although one can hide physical appearance or fool others, true feelings can never really be concealed from the heart.