/jp/ - Otaku Culture

Need help with the doppelganger quest. I know it's the princess from my last playthrough but I don't wanna do that whole follow her the whole day and wait for her to transform at some random interval and only upon witnessing this will the captain of the guard believe me. But what I'm asking is how do sequence break the quest as the captain of the guard is skeptical and when I attack the doppelganger/princess by flicking her forehead causing her to lose her concentration and her disguise the guards still attack me despite me being right, do I really have to do the quest all over again or is there way to skip to the end?