Question
I am an interior designer. Most of the time my customers ask me to help them purchase the products that they need in order to furnish the apartment whose interior I designed. I checked and keep checking into the people whose products I recommend to ensure that they are worthy of my recommendation. The common practice is for vendors to pay a commission to those who recommend them. They all pay the same percent. Thus, any person I will recommend will pay me but I only recommend those whom I really feel comfortable recommending. I have a client who mentioned several times that he doesn't want me to recommend people who pay me. Can I ignore this and recommend someone who will pay me without informing my customer? It is important to note that the dealer does not charge the customer anything extra because he pays me. Must I abide by my client's wishes or can I ignore them since it does not make any real difference to him and the only reason he does not want me to be paid is due to false assumptions.
Answer
As long as you do not tell your client anything that is not true, your only issue is whether you are violating the laws of geneivas da'as.
There are several proofs that one only violates the prohibition of geneivas da'as if the information that he is withholding truly makes a difference to the one who is being misled.
One proof is from a ruling of several poskim concerning a person seeking employment who wished to dye his white beard in order to gain a position. The question was asked to the Sefer Hamo'or (1, 26) who ruled that if the employee was fully suited for the position and the employer would not suffer any harm by hiring this employee, he was allowed to dye his beard even though the employer would not have hired the employee if he knew his true age. This ruling was fully agreed to by both the Levush Mordechai (res 24) and the Iggros Moshe (YD 2, 61). Thus, we see that even though the employer would not have hired the employee if he had known that his beard was white, nevertheless the employee did not violate the prohibition of geneivas da'as if he was really suited to the job.
There is another instance where we see that the Iggros Moshe maintains that withholding information that in truth is insignificant is not geneivas da'as. In this case a ba'alas teshuvo had relations with men many times before she became a true ba'alas teshuvo. Rav Moshe (OC 4, 118) ruled that she can inform her future chosson that once in a difficult situation she slipped up and had relations. (She had to divulge that she once had relations because otherwise her kesubo would be posul.) He explains that even though if the chosson knew the truth he would not marry her, nevertheless, since she was now a true ba'alas teshuvo and she would certainly not return to her former behavior, she is allowed to cover up her past.
In the Gemara as well we find several instances where an amoro who was certain of the halocho altered the facts in order to cause someone who did not know the halocho to act properly. One case (Eiruvin 51A) involved Rabboh and Rav Yosef who were traveling and Rabboh knew that they were allowed to continue their journey but Rav Yosef did not know that it was permitted. Since Rabboh was certain that they were allowed to continue, he stated that the Tanno, Rav Yosi maintained that they were allowed to continue even though Rav Yosi did not rule on this matter. The Gemara says the reason Rabboh's action was permitted was because Rabboh was certain of the halocho but Rav Yosef would not rely on him. Therefore, Rabboh was allowed to claim that Rav Yosi ruled that way since no harm would befall Rav Yosef as a result of his alteration of the facts. This behavior of Rabboh is ruled by the Magen Avrohom (siman 156).
This is similar to your case because the reason your client does not want you to receive anything from the vendors you recommend is because he thinks that perhaps the vendor will pass along the expense to him or perhaps your recommendation is influenced by the kickback you receive. But if you know that his fears are unjustified you can withhold the truth from him since his fears are groundless just like Rav Yosef's hesitation was groundless.
Another instance where we see in the Gemara (Brochos 53B) that a person was allowed to alter the facts, concerned an amoro who was traveling with others and forgot to say a brocho acharono before departing from the place he ate. Knowing that those who were traveling with him would not agree to wait for him to return to the place where he ate in order to make a brocho acharono, he informed them that he forgot a golden bird which was not true. (In the end Hashem made a miracle and he found a gold bird.) The reason the amoro was permitted to alter the facts is because had those who were traveling with him known that returning to say a brocho is more important than retrieving a lost golden bird, they would have readily agreed to return to the place he ate. Therefore, it was permitted for the amoro to alter the facts since by altering the facts he only caused his travel mates to act properly.
All the above is true if you don't need to lie. However, if your customer asks you if you receive anything from those you recommend, you are not permitted to lie since one may not lie in order to earn money. The Chafetz Chaim (Sefas Tomim chapter 2) cites the Midrash that sheker-falsehood wanted to gain admission to Noach's Ark and Noach refused until he brought his mate – loss – with him. The reason they were mates he explains, is because when one uses falsehoods to earn money, he will lose it. Therefore, you must not lie even if as a result you will forfeit the commission that the vendor will pay you.
In conclusion: You may withhold the information that you receive money from the vendors you recommend even though you know that your employer would not accept your recommendation if you divulged that information. However, you may not tell him that you do not receive anything from these vendors.
