Place broth in a 4 quart stock pot over medium heat; add kale and boil until just wilted, 10 to 15 minutes or until desired tenderness. Stir until all greens are wet. Add pork belly to a large skillet over medium heat and brown on all sides until golden and crisp. Remove from pan to a paper towel. Pour off all but 2 tablespoons of fat. Lower heat; add garlic to skillet, and sauté until garlic begins to sizzle. Add a pinch of red pepper flakes and sauté until the garlic is tender and lightly golden, 1 to 2 minutes longer. Pour kale, broth and pork belly into skillet and deglaze pan while sautéing kale until heated through, about 3 to 4 minutes. Serve with a side of cornbread.