If you aren't prepared for the simple equation of Sales = Rejection, a career in sales is going to be a very difficult road. Many of us are taught that rejection isn't fun, that's it's to be avoided, that it's embarrassing, etc.
That's the problem, the idea that rejection is negative. Like my Dad said to us, every day I might add, "be like a duck, let it roll right off your back"! So, if someone is going to be successful in a career in sales, they have to change their mindset to truly believe that rejection is an opportunity - an opportunity to try again, to get closer to the yes. You have to train yourself to be a punch clown - no matter how many times you are told no, you will come right back, to try again, with a smile on your face!
We have to learn and embrace that rejection is part of life, it's necessary, it's not personal and actually can be fun. If you want to reinforce your rejection armor or need to learn how to build your own, I cannot recommend enough Jia Jiang's TedTalk, What I Learned from 100 Days of Rejection: