Final answer:
Jack hesitates because of a moment of doubt in his ability to kill, promising next time to overcome his hesitation and carry out the act.
Step-by-step explanation:
Jack hesitates when he lifts the knife to kill the piglet because he feels uneasy about the act of killing; it is not the sight of blood or empathy for the piglet that stays his hand, nor is he a vegetarian with moral objections. Instead, his hesitation is due to a moment of doubt about his ability to actually go through with the violent act.
He promises that next time he will not hesitate; he will be more resolved to complete the deed, indicating that he intends to overcome his uncertainty and be ready to kill without reservation.