Rinse and pat dry the roast. Coat the roast evenly with the flour; season with salt and pepper.
Heat the olive oil in a skillet over medium-high heat. Add the garlic to the hot oil; sear the beef in the oil until all sides are slightly browned. Transfer the roast to a slow cooker. Pour the water over the roast.
Cook on Low for 5 hours. Add the anise seed and sesame seed to the slow cooker and cook another 4 hours. Add the green bell pepper and continue cooking until the meat is tender and easily pulled apart, about 1 hour more.