What is the ruling on money acquired from selling a commodity after the seller assured the buyer that it was suitable for him, even though he only intended to sell his commodity, and is this considered deception and cheating?

There is no harm in benefiting from the money acquired from this transaction, as long as the pillars of the sales contract are fulfilled. Concealing advice does not affect the validity of the sale, as the unsuitability of the garment is a relative matter. However, this deprives the seller of the reward for giving advice, and it would have been more appropriate for him to advise the buyer if he sought his advice.