There is a limited amount to the rejections one person can take. To make sales and perform well, one must create an armor-like shield.
Typically people need some confirmation now and then. A pat on the back or a mini-win that empowers.
Many jobs, outside of what is strictly considered as sales or business development, entail sales-like activities. More specifically, persuading people. When a nurse has to administer medicine to a patient, and the patient refuses, the nurse has to persuade the patient. Even though they might experience resistance, they will succeed eventually. Which feels like a win. People in sales have to be willing and able to go for prolonged periods without wins.
Persuading people to buy a product will inevitably be met with a lot of no’s. Brush that dirt off your shoulder and on to the next.