However, if he does not rectify his Nefesh completely the first time, when he leaves this world (dies), he will be required to return with his Nefesh in a gilgul (a reincarnation), even many times, until he purifies completely everything that he is required to. And so, after he completes his Nefesh, his Ruach is unable to join him (in this gilgul). This (the possible need for multiple gilgulim) is not a problem, as we will explain soon, with the help of Hashem (this is explained at the end of Ch. 3).
Therefore, [to get his Ruach,] he will need to leave this world, and his Nefesh will need to reincarnate into a second body. In this second gilgul, he will merit for his Ruach to join his Nefesh. And if he rectifies his Ruach [in this second gilgul], he will need to leave this world (and reincarnate into a third body). In this third gilgul, he will merit for his Neshama to join his Nefesh and his Ruach.
But if he did not rectify the Ruach [in the previous gilgul], he will be required to reincarnate [possibly] many times, each time the Nefesh will remain with the Ruach, until he rectifies the Ruach. Then, when he dies, he will need to return into another gilgul, where his Neshama will join his Nefesh and his Ruach until the three of them are rectified (completed). Once this happens, he will no longer require any reincarnation because his Neshama is complete, and from this, he becomes an "Adam Shalem" (or, a complete person).