Hayate actually considers her reply, since Bertie is her friend and all.

"It's just...I'm getting rusty, Bertie. I mean, in the past, I've died up to eight times in a single day in order to put down a threat, and now I'm worried that if something that needs that kind of dedication out of me comes along I might not be able to respond."

A pause as she ruffles her wings uncomfortably.

"...and if that happens, I'm basically failing you and everyone else in Ponyville."