I won't have to, Alfred. You'll know too.

At the end of chapter 12, Alfred decides to resume training because he wants to "know." The knowing pertains to whether or not he could have been a good boxer, and it also pertains to whether or not he is a tough enough person and has enough heart to be a contender. The knowing extends beyond the realm of boxing. Alfred looks for external validation from Mr. Donatelli—he wants someone to tell him that he has potential and that he can be special. Mr. Donatelli stresses the importance in realizing one's specialness for one's self, and Donatelli says that Alfred has the power to do that. He encourages Alfred to really trust and rely on what he knows and feels, rather than what anyone else does.