When a rumor starts about someone, being the one who says “I don’t believe that” can save their whole month.

Something spreading about a person picks up speed because everyone assumes somebody else has already checked it. One voice saying they do not buy it breaks that assumption and gives everyone in earshot permission to doubt it too. From the inside it feels like a small remark. From where the person is standing, it can be the difference between a bad fortnight and a ruined term.

You do not need proof to say you do not believe it. That sentence is enough. If you know the person, tell them afterwards that you said it, because knowing somebody spoke up matters more than you think.