He chose you to be his bride the moment he saw you...You weren't a noble nor were you someone with any type of social standing in general, but he still wanted you anyway, which is why he had Agni scoop you up and take you to the palace...

You were very confused, however, you weren't about to argue with a prince...He gave you a tour of the palace and proudly announced his engagement to you but proclaimed he wouldn't marry you until you were okay with it...So, now you're the prince's bride...