"Whoever believes in Him will not be disappointed."
Romans 9:33; Romans 10:11; 1 Peter 2:6; Isaiah 28:16 ("disturbed")
The sheer number of times this verse is quoted should signal that something important is being said. Disappointment is a sure sign of misplaced hope. The person who can say with the hymnwriter...
My hope is built on nothing less,
Than Jesus blood and righteousness
...is a person who can never be disappointed. His ultimate hope is far out of reach from all circumstances.