Interested in Language
Paul's lover comes to him and says that Bill (probably her husband) "is having us watched". Pauls looks through the window and sees some man. Says:
- OK, I'll take care of this.
- No. No, don't. Please. If that's what it is, you'll only make everything worse.
Breakfast at Tiffany's, movie
The marked phrase means:
If that's what it is = If surveillance is what the man standing below is...
Am I right?
"That" is probably her husband hiring a private eye to spy on them. Of course, it didn't turn out to be that.