Well, in context, that verse was addressed to the Israelites while they were enslaved. It was God telling them they He had plans to prosper them. We often get confused by this verse when we don't "prosper". So don't use this verse if you are disappointed in what God may have not done in your life. But God's plan is still perfect.
It was during that time, and while realizing that a reconciliation was not possible (he married someone else), that my pastor highlighted this passage and brought it to my attention.
The emphasis wasn't on the "prosper" part, but rather on the, "God wants to give you hope... and a future."