Final answer:
Macbeth considers assassinating King Duncan to become king after hearing the Witches' predictions, but struggles with the moral implications and his loyalty.
Step-by-step explanation:
After he hears the Witches' predictions, Macbeth considers taking action to become king by assassinating King Duncan. He ponders the consequences of the assassination and acknowledges that it would enable him to fulfill the prophecy, but also recognizes the moral implications and the potential for retribution. Macbeth contemplates the double trust he holds as both the king's kinsman and subject, and as his host, struggling with his loyalty and the ambition that has been sparked.