Halacha 2: If Reuvain and Shimon are already partners in business and you know Reuvain had a bad nature previously, either too lazy or not responsible with other people’s money, or under qualified, or poor now, then if you know that Shimon will only take what you say into account and be on top of things, like constantly checking the books that they are not losing money then you can warm him, albeit fulfilling on the conditions discussed earlier. But if you know that Shimon will take you seriously and take action to hurt Reuvain or immediately fire him without taking him to court then you can’t tell Shimon about Reuvain because who knows if Teuvain has changed. There is no indication right now that he’ll ruin the business. Maybe he shaped up or is better qualified than before. All you ate doing is definitely ruining Reuvain’s life, on a possibility that Shikon might be in trouble. Certainly, saying something on your own would be a problem if Shimon takes immediate action but even if you came with someone else as witnesses still it would be rechilus because if they would testify in court there would still be no grounds to fire him or hurt him in anyway. But if there are grounds to have him fired if brought to court then that was discussed earlier in hilchos rechilus 9:1,2, on what to do. Also, if you see the way things are going now in the partnership is going downhill, and Reuvain doesn’t notice that, then you can tell him, of course with meeting all the conditions discussed so that Reuvain won’t lose a lot of money.
Halacha 3: It is one thing to not speak badly about people but it’s another thing to give people bas advice to join with someone who will be harmful to them. That would be lifnei iver, placing a stumbling block in front of the blind and a very grave sin. So one cannot intentionally set up a shidduch or a business partnership, or tell someone to hire an electrician, plumber, etc. Which you would not do yourself in his same shoes because you know there is a problem because you will only be making trouble and that is forbidden. Unfortunately, many people give bad advice to make gain attention or to make money for themselves but it’s an unbelievable sin! Good Shabbos, Rabbi Dovid Shmuel Milder