One of my husband's brothers has cancer. It is a rare cancer that started in the lining of his lungs. It has been very aggressive with no radiation/chemo therapy slowing it down. He has suffered physically with blood clots, sickness from the medications, and difficulty breathing. He has suffered mentally, with each attempt to cure the cancer failing, he realizes that he will leave behind a wife and two daughters (ages 22 and 8). Even though he knows Jesus is his Savior, he and his family question why we have to suffer in such awful ways.
I know the context of this verse and those before it, is Jesus telling His disciples that following Him will bring persecution. I'm understand that, and am not taking the verse out of context. It's just this verse also reminds me that we will suffer on this earth. Satan is still the ruler of this world. Sin is still in this world. While we are residents in this world, even as a child of the King, we will suffer in all kinds of way. Jesus died on the cross so that we will have life with Him in heaven. Yes, making Jesus your Savior will bring peace to your human hearts, One day He will bring peace to this planet, but until then, plan to endure many trials that this life will bring.