How can a mother accept a 15-year-old child-like girl? Doctor Roudrik♥️Marry only on the word of his mother || 1

Roudrik had not met the girl named Rupa, nor her family. He had agreed to marry only on the word of his mother after many days. He had no desire to drag anyone into his life for the second time. Roudrik observed Turna carefully.
The girl would be quite younger than him. To say quite would be wrong, much younger than him. But more importantly, what would this girl do in place of the girl named Rupa? Roudrik again threw a serious question at Turna, who was gasping in front of him,

“Why are you in place of your elder sister? And who said that I am your groom?”