"To all who mourn in Israel, he will give a crown of beauty for ashes, a joyous blessing instead of mourning, festive praise instead of despair. In their righteousness, they will be like great oaks that the Lord has planted for his glory."
The whole chapter talks about how God takes what seems to be basically destroyed and restores it. How he took something that reeked of hopelessness and gave it beauty. But God makes it beautiful. And he is glorified through it all. That's a precious promise.