Hmm. I thought it was an off the cuff joke he was making, the way Della looked at him in reaction, kind of narrowing her eyes. I feel like if he WERE her fiance we’d have heard it mentioned by literally anybody else before this, Perry, Hazel, EB, even Hamilton to Perry, but I guess it could be a bearding arrangement they don’t talk much about. Oh, but another mark against it would be the huge conflict of interest it must be? At least for Barnes to cause some drama.
If this were a different show, one without all this history that it’s the origin story for, I would almost think it was foreshadowing an engagement precisely because of all the drama but it feels like a lavender marriage between existing characters Della Street and Hamilton Burger is a bit too far even for a 2020 reboot.