Mix together the seasonings: sage, salt, pepper and garlic.
Rub over tenderloin. Place 1/2 cup water in slow cooker; place tenderloin in slow cooker.
Cook on low for 6-8 hours.
1 hour before the roast is finished, mix together the ingredients for the glaze in a small sauce pan: brown sugar, cornstarch, balsamic vinegar, water, soy sauce.
Heat over medium and stir until mixture thickens, about 4 minutes.
Brush roast with glaze 2 or 3 times during the last hour of cooking.
For a more caramelized crust: remove from crock pot and place on aluminum lined sheet pan, glaze, and set under broiler for 1-2 minutes until bubbly and caramelized. Repeat 2 to 3 more times until desired crust is achieved.
