Cassidy has been more elated than what Adrian expected.
When he went and bought her a cone of strawberry ice cream, her bright, dazzling smile never left her face. She expressed her gratitude with the giddiest of grins he has ever seen before proceeding to feast on the sweet with so much delight. He couldn't take his eyes off of her starting from that point on.
It was his first time experiencing something like this. His disguise may have helped, but he felt like he was being treated genuinely for once. There was no facade that could serve as a barrier between her and him. Both of them are acting as their own persons - not at all influenced by each other's background, status, or anything related to that.
Apart from that, there is something about Cassidy that Adrian has never seen from anyone else. Perhaps, not just something - it is her as a whole. She can be both wild and clumsy yet soft-hearted and sincere.