In this chapter, we learn that the devil's plan is to get rid of all of the good memories of the two of them, so that he can forget all the bad ones. In other words, the devil wants to make sure that if he gets rid of the bad memories, he'll be able to forget the good ones as well. This means that, even if the devil doesn't lose all of his good memories, the two will still be in love with each other. But that's not going to happen, because the devil still wants to keep all of their good memories. In fact, the only thing that will keep them from falling in love again is if they live together and touch each other, which is what they've been waiting for for 200 years.