"There are three things a wise man fears: the moonless night, the stormy sea, and the wrath of a kind man."
And Hana-chan is very, very kind...
I think it went like "the sea in storm, a night with no moon, and the anger of a gentle man", but the gist is right. Never anger an all-loving heroine.
Yes, that's it, thank you. I was paraphrasing from memory the Spanish translation I read when it came out.
Fifteen years since, still waiting for the third book...