Halacha 1: One may not accept rechilus as fact even if it was said in front of 3 people or more. That doesn’t give any validity just be cautious and investigate if it’s a matter of a potential threat, for example if some one told you in a crowd that someone else wants to hurt you or said bad things about you then you can ask others if this is true or not and investigate. But if there is no threat then one is forbidden to clarify whether it actually happened or was said because you will definitely be placing a stumbling block in front if the blind, since people will feel they have to answer you if you ask and they will be speaking rechilus if there is no potential threat.
Halacha 2: Even the rechilus is said in the face of the perpetrator, for example Reuvain is looking at Levi and tells Shimon, “You are the one who said such and such disgrace about Shimon,” now even if Levi was quiet a d didn’t defend himself when the rechilus about him was said right in front of him, still Shimon cannot believe it as fact. Even if the nature of Levi is usually to always speak up and defend himself and this time he didn’t so it looks like he is admitting he said it, still there is no proof that that’s a actually true. This is true even if the Reuvain was allowed to tell Shimon because of a possible threat that Shimon should watch out for, still he can’t believe it just be cautious and take proper precautions, and surely if he spoke regular lashon hara or rechilus which there is no potential threat to anyone, Shimon may not believe Reuvain because he surely is wicked for transgressing the prohibition of rechilus so how can Shimon now believe this bad person who is trying to make someone else look bad?
Halacha 3: If one has a damage in business and he is unsure how it happened, for examole he was kicked out of his rental but he is unsure where someone smeared him and got him kicked or the landlord himself decides he didn’t like him and kicked him off the land. He can’t suspect that any Jew was out to get him unless he has circumstantial evidence, which will be discussed in more detail later, but then he can decide the Jew was out to get him, but that does not mean that he has a right to go after that person’s assets. The reason why this is true is because we don’t assume a Jew would do such a wicked thing as the Torah (Vayikra 19:15) states, “You shall judge your nation righteously.” Even if one heard that a certain Jew caused the damage, he still can’t believe and should only be concerned about what he heard and look into the matter, but not decide that what he heard is true. Even if people were out to get this guy who supposedly got the tenant into trouble and they told the tenant that this guy did it and the guy was quiet and didn’t deny that he wasn’t the cause, still the tenant can’t decide that this is in fact true, that he was the perpetrator, because even though there is a mitzvah to save oneself from acquiring a bad name and must save his own self from suspicion as it says (Bamidbar 32:22), “you shall be clean from before Hashem and the Jewish people” nevertheless divine sees any excuse will not be listened and there is no point in speaking up he has a right to stay quiet and be among those who are insulted and don’t insult back, they listen to disgrace and don’t answer about these people it is said in Chullin 89a, “upon whom does the world continue to exist, by those who keep their mouth shut at a time of argument. “