How long does it take for arona to ask about her ghost set?

[Lostname475]

I took her to fort marrok a few days ago but haven't been able to get the quest off her

 

[LeDoraggo]

I was about to ask the exact same question. In my last save, i went there and inmediately that same night i got the quest prompt. However, i did the same in my newer save and it's been fifteen or so days in game and she seems to have gotten over her fear of ghosts all of a sudden