Sister-Brother Love: Sister, I Will Protect You in the Next Life!

I was born into a wealthy family, but my brothers are all like that, so temperamental, but why don't I have that temperament? Once again, I secretly took my brother's hair for a DNI test! But in the end it was confirmed that they were biological siblings! But why are my temperaments so different from those of my brother? My brother is so evil and charming, but I am a little cute at best, hehe, he is narcissistic. But I never expected that I would fall in love with my brother. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.