Trump forgot the “sarc” tag when he said that.
Trump is way above the media and the audience as a “pick up artist” here:
https://reason.com/blog/2015/09/15/trump-as-political-pick-up-artist-the-do
The “Carly you’re beautiful” was a double neg in that Trump was being sarcastic but he knew it would be taken as sarcasm by the audience and Carly.