nothing comes out of nothing 无风不起浪

“无风不起浪”，字面意思是“there are no waves without wind”，形容事情的发生总有起因。可以翻译为“nothing comes out of nothing，everything has its seed”等。

例句：

起初他并不相信这些谣言，但仔细想想觉得无风不起浪。

At first he didn’t believe the rumors, but on second thought he realized that there must have been some reason for them.