Because of how he reacted to her in the dress felt it was kinda obvious at that point
My train of thought when he reacted to that dress was "Ohhh... so both brothers were scheming, and then the younger brother disguised himself as his older brother to sneak in at that party" hence why the princess think both brothers have same taste in woman
Ohhh fair but his reaction to the dress clicked that he was pretending to be his brother for me
yeah i never thought of that. still, it's a good twist in a story
whoever said that you've seen this coming must be a big fat liar or have been watching too much semi-fictional criminal documentaries, bcz HOW COULD YOU SEE THAT COMING????