('chiefly US') cities in the 'Rust Belt' [=an area formerly known for industry and manufacturing]
When you're riding in a car, you should always 'belt up' [=('US') 'buckle up'] for safety.
That remark was 'below the belt'. = That remark really 'hit' (him) 'below the belt'.
(..) Yes. Back then, I used humor as a defense mechanism. Thank God I don't do that anymore. What you have been doing since childhood? Well, I got a new belt. I wondered! - Oh, my God! - What? What? It's Jean-Claude Van Damme. I didn't know he was in (..)1996 TvShow: Friends Title: The One After the Superbowl: Part 1 Season: 2 Episode 12