Rinse the pork tenderloin with cold water and pat dry with a paper towel.

In a bowl, combine honey, soy sauce, oyster sauce, brown sugar, minced ginger, minced garlic, ketchup, onion powder, cayenne, and cinnamon.

Pour the marinade over the pork tenderloin, ensuring it's well coated.

Cover the pork and refrigerate for 8-24 hours, turning a couple of times to ensure even marination.

Remove the pork from the marinade, reserving the marinade.

Season the pork with salt and pepper.

Arrange the pork on an oiled grill rack.

Grill the pork, basting with the reserved marinade and turning every 3 minutes until cooked through.

Discard the remaining marinade.

Let the pork rest for at least 7 minutes before slicing.

Slice and serve.