Only the author knows if those girls really are twins ╮(￣▽￣)╭ I just have a ta...

But the prince already appraised them and they are labeled as twins. If they're not then the appraisal magic is a fraud?

I just think one looks just like the mother and the other looks just like the father
( but that isn’t confirmed since we don’t know how the father looks like)

They are not twins, basically the FM real mother died at childbirth and at the same time that b**ch mother gave birth to the to b**ch daughter, the father didn't wanted the FM to get treated badly so he lied to the b**ch mother that she had twins. The father was committing adultery (I think, I read the novel few months ago so I don't remeber the detail)

Rather than using appraisal, I think the prince just knew because he was a reincarnated being, (that's what elemental spirit king said). I doubt that he appraised it cause he also knew her location, so the possibility of them not being twins is high