If he actually understood that she's choosing their school to be with him of her free will, Sorata would would also have accepted that she has special for him.
Her intentions are not clear-cut to him because they're being obfuscated by the will of her grandfather, whom he knows Miyuki holds...
I'm freaking the fcuk out. Of course he should have just smiled and say he was grateful to be spending time with her. In fact, when they're together and married he should continue to say "Thanks for turning down those opportunities to be with me." 🙄 Jeez are we reading from the same PoV...