Aside from what White says, it's fair to add that it's going to take more than White's voice to seal the deal. It's been quite a journey for fans waiting to see what would come of this particular franchise, so for lack of a better way to put it, it's all pretty much wait-and-see at this point.
With regard to Never Back Down 3, White teased this a bit last August when posting a photo with actor Djimon Hounsou who lended a supporting role to the 2008 film alongside lead actor Sean Faris. The 2011 sequel, saw the portrayal of White as an ex-con long since established as an MMA trainer to a group of young boys as two within the group prepare to face each other off in the titular underground MMA contest. As for the title he teased back then, that may be a different story, but the best news so far from this is that White did, in fact, confirm he would return to direct as well as star, to which he added some more thoughts about how his character would progress.