Shirou
Shirou gave the enthusiastic girl a kind smile.
"Yes, she did seem very nice, although I've only met her once", he said. "I don't know of any Sakura who was that strong, though."
Sakura
Sakura looked at her lookalike with confusion, wondering what the hell she was talking about. It seemed like a "Senpai" was, to her, some kind of special role filled by what she referred to as "humans", presumably the ordinary, non "Sakura" people living in her world, and this one, but why would they make it illegal to marry wonderful people like Shirou? The more she heard of it, the weirder Mary's world sounded.
"I don't understand. Why wouldn't you marry the person you love?" she said, glancing lovingly at Shirou as she spoke.
Then, she turned to the other girl, a kind smile on her face.
"That's an interesting theory, but it couldn't be true", she replied. "I'm not originally from this world, and none of my family look like me, at least not to the extent that Mary does."
With that, she turned back to Mary.
"Could you explain more about your world, please?" she said, politely. "That might help us understand what is going on."