When something is diverting, it is entertaining in a gentle way: it keeps your mind happily busy, so worries step aside for a while. A diverting story, play, or evening does not have to be loud or silly; it just pleasantly takes you somewhere else. Though actually, this is a rather bookish word. Young people almost never say it on the street. You will meet it in reviews, in novels, and when someone wants to sound polite or a little old-fashioned. Everyday English would just say fun, entertaining, or amusing. One extra truth: the same spelling also appears when we talk about diverting traffic (sending cars another way). That is the verb divert. Here the word is an adjective: if a film was diverting, it kept you nicely amused.