It's a metaphor for how repeated rumors, even if false, can cause people to believe and then become doubtful, even about someone they deeply trust.
谣言的可怕之处在于，即使是亲近的人，在三告投杼之后，也难免会产生怀疑。
The terrifying aspect of rumors is that even those close to you, after being subjected to repeated false reports, will inevitably begin to harbor doubts.
Era:
Ancient
Frequency:
Story:
During the Spring and Autumn period, a man in the Fèi region, who happened to have the same name as Zeng Can, committed murder. A busybody rushed to Zeng Can's mother and reported, "Zeng Can has killed someone!"
Zeng's mother calmly replied, "My son would never kill anyone," and continued weaving as usual.
Shortly after, two more people came, mistakenly reporting the same news that Zeng Can had committed murder. At this point, Zeng's mother became terrified, threw down her weaving shuttle, and fled by climbing over the wall.
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