Place pork tenderloin in 2-4 quart crock pot, cutting in half lengthwise to fit flat if necessary.
In a large bowl or glass measuring cup, whisk together cranberry sauce, sugar, broth, vinegar, corn starch, garlic, salt and pepper. Pour over tenderloin in crock pot, lifting the pork to let the sauce seep underneath.
Cover and cook on high for 2 hours or low for 4 hours, or until it reaches an internal temperature of 150-165 degrees. Remove pork and place on a cutting board to rest for 3-5 minutes.
If desired, add an additional tablespoon of corn starch mixed with a tablespoon of water to thicken remaining juices.
Slice and serve with sauce.
