Looks like a win-win for you. If you are wrong, she'll be set for life financially and you won't have to worry about supporting her. If you are right, you get a great big, "I told you so."

I know that gearing up for a great big “I told you so” probably feels way more satisfying, but please don’t actually do that. When your daughter finally sees reality, you’d want her to be able to come to you for help in leaving the guy who’s mistreating her, right? Continually insisting that she’s dumb for thinking this will just end up pushing her away and make her feel like she can’t come to you. As much as it’ll suck to do so, keep things civil with her and talk to her about anything else but the boyfriend.

Ask yourself this: Do you want to help and support her, or do you want to be the "I told you so"-guy? If the latter, then by all means go ahead and push her away and make her life worse. If not, then be there!

as someone who was young and slightly more stupid than I am now, you don't want to tell you kid how stupid they actually are. it can cause them to not only not listen out of spite, but then not call you if something bad happens, like say they wind up in jail for instance for trusting the wrong people... the point is, you can be the one who was right and smarter, or the one who helps get through the bad times that will probably come and be seen as someone who knows what they are talking about.

You raised her, or at least should have had some degree of involvement in the process, so this is at least partly your own fault

Your job was to model healthy relationships. She can't identify one.