the proof of the pudding (is in the eating) idiom saying (also the proof is in the pudding)
布丁好不好，吃了才知道（只有通过体验才能判断事物的好坏;空谈不如实证）
said to mean that you can only judge the quality of something after you have tried, used, or experienced it
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。