Rejection of any kind is difficult to handle. And I’m not just talking doors slammed in your face or shouted slurs or something quite so obvious, because the tough reality of life and missionary work is that you will be rejected very often. It might not be a major rejection; it may be as simple as “I didn’t read the Book of Mormon this week” or “I don’t want to go to church this week” or something similar.
Take a word of advice from a seasoned Elder: don’t worry about it!
Throughout the course of my mission, I have been rejected hundreds of times. We are rejected multiple times a day, every day. A day will not go by that you do not face some sort of rejection.