Origin
Hoenn Confirmed originated on YouTube in 2012, when ROMs of Pokemon Black 2 and White 2 were leaked. A remix of the Hoenn Trainer Theme was found on the forum board 2ch, a board on which users were sent copies of Pokemon Black 2 and White 2 early. While the remix was later found to be unofficial, it spread around YouTube. A common comment on videos featuring this remix was “Hoenn Confirmed!”
Spread
Later, when the official remixes of the Hoenn Gym Leader and Hoenn Champion Battle themes were ripped from the ROMs of Black 2 and White 2, the “Hoenn Confirmed” comments continued.
Derivatives
Eventually, people started making the “Hoenn Confirmed” comments with “exaggerated” sounds, typing it as “HURRNN CUNFRMD” or “HURREN CONFURMED”, etc.