That's not what I said either. If you read my theory, it says that 1) Terra's heart would be locked inside his body, which had been taken over by Xehanort and eventually turned into a heartless and 2) when this heartless body was exposed to pure light, it stripped away all the darkness (meaning the body, Xehanort and the darkness in Terra's heart). This would leave Terra's heart, which obviously had both light and darkness in it to begin with, free from darkness - similar to what happened to Ventus. This would open up the possibility of Terra's heart, now stripped of darkness and no longer locked by Xehanort, but just like with Ventus, Terra would be in deep sleep to recover somewhere (and who knows, maybe something similar to Vanitas was created in this process).