what's wrong with 'the dress suits her perfectly'??
Man ville vist bruge passer til hende for det. (From what I've heard, you would use "passer til hende" for that.)
Fair question, I was wondering the same. Probably has to do with the options presented to the system?
The dress fits her perfect! is not an acceptable answer to Duolingo. Really?
Does it also fit her plusquamperfect and her subjunctive? ;-)
Usually you need an adverb to add information to a verb, not an adjective.