He doesn't miss her reaction, but he genuinely has no idea what the issue could be, when cursing is just second nature and everyone does it.

"I know I'm real handsome, pumpkin, but no need to get so flustered!" He's doubtful that's actually what she's upset about, but he's not going to let something like the truth get in the way of either his ego. Plus he's kind of curious to know what's actually bothering her, and this is the best way to find out.