[The answer is near-instantaneous, and it comes before she really places Hiyori's voice. To be completely fair, she doesn't know him that well yet, and her experience so far with him talking has been him mocking her every time he opens his mouth.
When she turns to face him, her expression is bright-eyed and sincere.]
I—
[...aaaand then she realizes who's talking to her.]
1/2
[The answer is near-instantaneous, and it comes before she really places Hiyori's voice. To be completely fair, she doesn't know him that well yet, and her experience so far with him talking has been him mocking her every time he opens his mouth.
When she turns to face him, her expression is bright-eyed and sincere.]
I—
[...aaaand then she realizes who's talking to her.]