What does it mean to inform someone about a situation or event?

To inform someone about a situation or event means to provide them with necessary details or updates, which is accurately encapsulated by the term "apprise." This term specifically denotes the act of making someone aware or informed about something, often involving communication of important information or developments.

On the other hand, "avow" refers to affirming or declaring something openly, typically about one's beliefs or feelings, rather than simply providing information. "Broach" means to introduce or bring up a topic for discussion, which is broader than just informing someone. "Asunder" describes something that is separated or apart, lacking any relation to the act of informing or communication. Thus, "apprise" stands out as the most fitting choice for conveying the action of informing someone.