@sandamckitty Same womb means same mother, although as the MC already said, that's not the turth since they don't come from the same mother. Nonetheless, that's what those who are not involved or know the story like the MC believe.
Hope that cleared out some doubts
I'm confused is there a translation mess up? I thought she was the younger sister by a year or so so why is she "born at the same time" as her brother ? Are they supposedly twins?