Unquestionably, the omission of the character Fortinbras from Shakespeare's Hamlet would greatly affect the development of Hamlet himself as a character. Much like Sydney Carton of Dickens's A Tale of Two Cities, who upon observing the sterling character of Charles Darnay, perceives in this man the idealism which he himself has lost to his dissipation, Hamlet, too, watches and listens to the noble and "tender prince," Fortinbras,
Whose spirit, with divine ambition puffed,
Makes mouths at the invisible event. (5.4.48-49)
and perceives in him an integrity of soul that he has set aside. Thus, like Carton who is moved to noble action by recognizing in Darnay what he could have been, so, too, is Hamlet inspired by Fortinbras, who, in the name of honor, is ready to avenge his father's death "Even for an eggshell" (5.4.53).
As a foil to Hamlet, Fortinbras acts as the catalyst to action for the prince of Denmark, inspiring Hamlet with his integrity and sense of honor to put aside his self-debate and charades with others. And, as such a representative of integrity, it is only fitting that while Hamlet dies he should bequeath the kingdom of Denmark, which he has cured of its "rottenness," to Fortinbras, whose very name suggests good fortune. Without doubt, Fortinbras plays a key role in the psychological development of Hamlet and the motif of Play-acting versus Genuineness.