Which word best describes "gain the good will of"?

The word "mollify" is particularly well-suited to describe the act of gaining someone's goodwill. This term means to calm someone down or to make them more agreeable, often by appeasing them or addressing their concerns. When you mollify someone, you are essentially trying to earn their favor and create a positive relationship, which aligns perfectly with the concept of gaining goodwill.

In contrast, the other options convey different meanings that do not align with the idea of fostering positive relations. For example, "oppress" suggests imposing burdens or hardships, which is antithetical to gaining goodwill. "Neglect" refers to failing to care for someone or something, which could damage a relationship rather than improve it. Lastly, "instigate" typically means to provoke or stir up trouble, which is again contrary to the notion of fostering goodwill.