Sprinkle pork with 1/2 teaspoon salt and the pepper. Heat oil in 12-inch skillet over medium-high heat. Cook half of the pork in oil 5 to 8 minutes, stirring occasionally, until pork is brown; place in 3- to 4-quart slow cooker. Repeat with remaining pork.
Add sweet potatoes, frozen lima beans, broth, 1/2 teaspoon salt, the thyme and sage to pork in cooker.
Cover and cook on Low heat setting 7 to 8 hours.
Stir together water and cornstarch; stir into pork mixture. Increase heat setting to High. Cover and cook about 15 minutes or until mixture is thickened.