[Chrom smiles. He doesn't know Chiaki well, but he's pleased by her commitment and promptness. It does make him wonder if she has a personal interest, considering the swiftness of the reply.]

Dear Chiaki,

Thank you for your support. I assume you must have your own reasons for wishing to protect this city, but I would not wish to pry. Keep your eyes open for any opportunities, as I do not know who possesses a sapphire crystal or where we might obtain one.

Sincerely,
Chrom