以为你都懂所以没说痛
[yĭ wéi nĭ dōu dŏng suŏ yĭ méi shuō tòng]
It means 'I didn't tell you how painful it was because I thought you understood everything.' It expresses the helplessness and grievances caused by misunderstanding in a relationship or situation, believing that both parties could communicate and understand each other, but later realized that this feeling of hurt had not been expressed.