千言万语不如你一个微笑
[qiān yán wàn yŭ bù rú nĭ yī gè wēi xiào]
It means 'thousands of words are not as good as your one smile', emphasizing that one's beautiful smile can surpass any other form of beauty or charm. The user wants to say the loved one's smile touches his heart so deeply it leaves him speechless.