User blog comment:FairyRaven/Fairy Tail Chapter 448: Fight the Power! Review and Commentary/@comment-24264679-20150817160616/@comment-7418318-20150821062758

Well... he did try to kill Makarov right away, instead of trying to get the information out of him, which speaks of a certain confidence that he can find Fairy Heart on his own.

But then he's immortal, so he literally has all the time in the world to find it. He could search (or have others search for him) for centuries if need be.