"If your missionaries wonder why this isn't easy, they should remember they are not the first ones to ask that. someone a lot greater and a lot better asked it a long time ago...
"If the missionaries can come to love and appreciate it, the Atonement will carry them, perhaps more importantly than it will carry their investigators... when they struggle, when they are rejected, when they're spit upon and cast out, and made a hiss and a byword, they are standing shoulder to shoulder with the best life this world has ever known, the only pure and perfect missionary that ever lived."
Missionary work is not easy. Not one bit.
But every moment will be completely worth the tears, prayers, and sweat.