To determine what is suggested about the character’s personality by the author’s use of understatement, we would need to consider how the character's traits are conveyed through the subtlety of their description.
If the character is described in a way that downplays their wealth or status, it could suggest that they might be uncomfortable with their wealth. Therefore, "The character might be uncomfortable with their wealth" would be a reasonable interpretation in that case.
If other traits are illuminated through understatement (for example, if they dismiss their accomplishments or avoid drawing attention to themselves), that could imply they are secretive or humble.
However, without the specific excerpt provided, we can't definitively conclude which interpretation is the most accurate. Based on your options, the nuanced suggestion could lean toward discomfort with wealth or possibly secretiveness, depending on context.
If you want to choose from the options listed, "The character might be uncomfortable with their wealth" seems like a strong choice if the understatement relates to their financial status.