There is nowhere in the Bible that says we as human beings will never feel discomfort. That we will never experience pain of the heart. That we will never get sick. No there are no words that say that. What the Bible does say is Luke 1:37 For nothing will be impossible with God. The Bible also says Deuteronomy: 31:6 Be strong and courageous. Do not fear or be in dread of them, for it is the Lord your God who goes with you. He will not leave you or forsake you.
The Bible gives us instruction on the expectations of God. The Bible points out man's sins. The Bible let's us know what is most important to God. That we must have a steadfast faith, that never waivers. Without doubt.
James 1:6 But let him ask in faith, with no doubting, for the one who doubts is like a wave of the sea that is driven and tossed by the wind