Preheat the oven to 425 degrees F. Set the pork in a roasting pan; brush with the oil. Sprinkle with salt, pepper and sage. Roast 20 minutes, and then reduce oven temperature to 325 degrees F. Continue roasting for 90 minutes or until the centre of the meat registers 160 degrees F on an instant-read meat thermometer. Transfer the pork to a large plate, tent with foil and let rest 10 minutes before slicing into portions. While the pork rests, drain excess fat from the roasting pan and set on the stovetop over medium-high heat. Add the pomegranate juice, jelly, wine, shallot, vinegar, peppercorns and honey. Bring to a simmer, stirring to dissolve the jelly. Pour in the stock/starch mixture, return to a simmer, and simmer until a lightly thickened sauce forms, about 2 to 3 minutes. Season the sauce with salt and pepper and serve alongside the pork.