How did you know?

Kira immediately noticed the extreme fear on Zeri's expression as he leaned in on her. The boy in disguise whom he was planning to kiss was unexpectedly looking much worse than he imagined.  

She wasn't looking at him. Her eyes were focused on the ground instead. 

Kira lifted his hand, held her chin and made her look at him. He didn't like the feeling of seeing this girl in this state, no, he strangely hated it so much. 

A flare of anger blazed within him as soon as he saw her lips trembling. He didn't expect this. He had felt that she was scared a while ago but he never would have thought that her fear was to this extent. Why was this girl looking this scared?