no smoke without fire

there's no smoke without fire

There is usually truth behind a rumor, suspicion, or bad sign. We decided to investigate the company's financial statements, since they had been paying next to no tax even though their profits were way up. There's no smoke without fire, after all. A lot of people have been saying that he cheated on the exam, and while I don't want to believe it, there's no smoke without fire.
See also: fire, no, smoke, without
Farlex Dictionary of Idioms.

(There's) no smoke without fire.

 and Where there's smoke there's fire.
Prov. There is usually some truth behind every rumor. I'm going to withdraw all my money from that bank. I read an article that the bank was in financial trouble, and where there's smoke there's fire.
See also: fire, no, smoke, without
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

no smoke without fire (or where there's smoke there's fire)

there's always some reason for a rumour. proverb
1998 Times This is not saying that there is no smoke without fire—which sentiment underlines why bogus claims can do so much irrevocable damage—but that this is always, necessarily, going to be an incendiary issue.
See also: fire, no, smoke, without
Farlex Partner Idioms Dictionary
See also:
  • no smoke without fire, there's
  • Is there any truth to (something)?
  • Is there any truth to?
  • rumor monger
  • nothing in (something)
  • nothing in it
  • be in the pay of (someone or something)
  • be in the pay of somebody/something
  • odor
  • be in good/bad odour