User blog comment:Crazylittlefreakgirl/Fairy Tail Official Pairings?/@comment-98.230.73.28-20140129153220/@comment-1776824-20140129153737

Confirmed means Hiro Mashima himself has directly stated that they like each other. Nalu and Gruvia are not like Jerza and Albis because they have not been stated to be official pairings. This makes them not canon by all stretches of the definition.