The Heir thing can be due to the fact in the the past in the medieval era if your sibling was the heir it means you have more power and support and your husband gets that power as well so as you can see that is why since the prince didn't fall in love first he had chosen the other girl BUT now that he has taken a liking he will chose her probably.
Usual Yashiro- Bring on da sexy manz~
Current Yashiro- Hakako-Kun and Aoi~ I MISSS YOUUUUUUU *sob*
Sorry I accidentally pressed dislike... i wanted to like ╥﹏╥
it be like that sometimes.