no smoke without fire, there's - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Also, where there's smoke there's fire. A suspicion or rumor usually has a basis in fact, as in When the sales figures continued strong but the company still wasn't making money, he suspected something was wrong—there's no smoke without fire. First stated in the late 1300s, this expression appeared in numerous proverb collections from 1546 on and remains current today.