Hamlet starts off by expressing wonder that an actor can present himself as so emotional and sincere over nothing at all-over just an act. He states of the actor,
"It is not monstrous that this player here, but in a fiction...could force...tears in his eyes, distraction in's aspect, a broken voice...and all for nothing!"
and yet, he himself, who has actual reason to be passionate and upset,, who has "the motive and the cue for passion" that he does, can't elicit that same conviction within himself. He, if expressing his true feelings about his situation, could "drown the stage with tears...and amaze indeed" if he were on stage. But instead, here he sits, "a dull and muddy-mettled rascal" who can "say nothing" not even for
"a king upon whose property and most dear life a damn'd defeat was made."
He wonders if he is a coward, because all he does is "unpack his heart with words and fall acursing." He lectures himself, saying, "About, brain!", meaning, take some action, turn about, do something, anything! At the end of the soliloquy he resolves to use the play to catch the king; if the king reacts, he'll know that he has "grounds more relative" than a ghost who "may be the devil [who]...abuses me to damn me."
His flaw of hesitation is revealed here through the fact that he knows he is hesitating; in fact, he rants against himself for it. He feels he is a coward for not acting. But still, he can't get over the fact that maybe, just maybe, the ghost was not a "good" ghost; maybe the ghost is the devil, using Hamlet's hatred of Claudius to invent a reason to kill him. He's so hung up on this-but hating himself for being hung up-that he comforts himself by deciding to use the play as a way to determine the king's guilt. His mental state is anguished, searching for a solution and middle-ground between action and proof. He goes back and forth, hating himself for hesitating, yet justifying his hesitation. It is a tormented soliloquy that show's Hamlet's torn frame of mind.