What does it mean to influence someone to adopt a new belief or cause?

The term that means to influence someone to adopt a new belief or cause is "proselytize." This word is often used in the context of religious beliefs but can also apply to political or philosophical ideologies. It captures the essence of persuading or attempting to convert someone to a particular point of view or belief system, indicating an active effort to spread or advocate for those beliefs.

In contrast, "proclaim" signifies announcing something publicly, which doesn’t necessarily involve persuading someone to change their beliefs. "Ameliorate" means to make something better or improve a situation, which is unrelated to influencing beliefs. "Diminutive" refers to something that is small or insignificant in size or amount, and therefore does not relate to the act of influencing or persuading in terms of beliefs or causes.