We’d want to avoid deceit, too, but that’s not easy either, and most especially in our professional lives.
“You might reason,” for example, as Ramchal points out, “that it’s only right … to make a product you’re selling … seem as attractive as possible”. And so you might speak of it in glowing (i.e., downright blazing) terms to make it sound enticing. But we’d been enjoined not to deceive anyone (see Leviticus 25:17 as well as Chullin 94a), and the prophet swore that “The remnant of Israel will not commit iniquity, will not speak falsely; (and that) no trickery will be found in their mouths” (Zephaniah 3:13).
As such, we were warned “not to paint-over old wares to make them seem new”, and to “not mix together different bunches of fruit — even new fruit with other new (but still inferior) fruit; even high priced (but undesirable fruit) with low — so as to sell the higher priced for less” (Baba Metziah 60a), to avoid deception.
(Yes but, “how can I not try to point out the value of my product to my customers?” you might ask. But as Ramchal underscores, “there’s a difference between pointing out the true value, worth or beauty of a product — which is a perfectly honest and honorable action — and covering over the product’s imperfections, which is deceitful and therefore forbidden”. In other words, you can sell an item’s selling- points, to be sure, but not play hide-and-seek with its faults.) In any event, the “stumbling-blocks on the path to (selling things) are as numerous as the yearnings for possessions”, so a great deal of “profound self-reflection is needed to actually free yourself” from falling sway to your inclinations. Understand, though, that “if you do manage to free yourself” of the temptation to deceive, Ramchal assures us all, “you’ll have reached a very great level which many who have attained several of the many levels of righteousness would not have” since it’s so challenging.