Season the pork roast on all sides with sage, salt, and pepper.
Place pork, fat capside up, in the slow cooker and sprinkle the garlic evenly over the top.
Carefully add water into the slow cooker so you don’t wash off the seasoning.
Cook on high for 4 to 6 hours, or until the pork shreds easily with a fork.
Carefully pull the roast from the slow cooker and place on an aluminum lined sheet pan, and let it rest.
While the roast is resting, make the glaze. In a small saucepan mix the ingredients for the glaze: brown sugar, balsamic vinegar, soy sauce, and cornstarch mixed with the water. Heat over medium, stirring until mixture thickens, about 4 minutes.
Preheat your oven broiler.
Pourabout half the glaze into a gravy boat and set aside.
Brush about half of the remaining glaze onto the pork and set under broiler for 1 to 2 minutes, until bubbly and caramelized.
Repeat 2 to 3 more times until desired coating is achieved.
Shred or slice pork against the grain into individual portions. Serve with reserved glaze on the side.