To succeed, you need to use the truth.
For example, you own an auto repair shop and give estimates to repair cars. Sometimes, you exaggerate a customer's problem so you can charge him more. This increases your income, but causes you problems. The customer senses your lie, no matter how sincere you act. When you are caught, the penalties are painful.
On the other hand, if you understate the customer's auto repair problem, you are compromising what you know to be true. You actually prevent your customer from making good decisions. You feel like a wimp.
You learn that the only way to behave is to look your customer in the eye, without hesitation, and tell the truth. The customer can then act accordingly. You do your job, even if you don't make as much money on that particular job, and even if the person doesn't like the truth.