Final answer:
The narrator has strong convictions, demonstrated by his choice to reenlist in the military due to his opposition to slavery despite experiencing significant hardships.
Step-by-step explanation:
The inference that can be made about the narrator based on the provided text is that he has strong convictions. Despite experiencing hardship such as battles, sickness, and lack of sleep, and losing his desire for adventure, the narrator chose to reenlist in the military. His decision was driven by his opposition to slavery, showing that his principles regarding freedom and justice were more influential than his personal comfort, indicating a strong moral compass and a sense of duty towards combating slavery.