Darcy/Thorin
If you see it in a RomCom, don't do it. omfg.
Then your best bet is to keep it sweet and simple. Her favorite wine, her favorite food, pop down on one knee, tell her how you feel etc. Bada bing, bada boom.
And fyi in my experience a lot of women who had TERRIBLE first marriages are pretty ok with trying it again with someone completely decent. Scott's dad is Douche #1.