Correct

无风不起浪

/ wú fēng bù qǐ làng /
Strokes

Definition

lit. without wind there cannot be waves (idiom); there must be a reason/no smoke without fire

Example

Definition

there are no waves without wind; there's no smoke without fire; nothing comes out of nothing; where there's reek, there's heat; everything has its seed

1
chū
起初
bìng
xiāngxìn
相信
zhèxiē
这些
yáoyán
谣言
  
,
dàn
仔细
xiǎngxiǎng
想想
juéde
觉得
fēnglàng
无风不起浪
  

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