It's implicit in the very fact of asking in that situation. Your response, and the neighboring one from ddoolin, is the equivalent of "I wasn't threatening her, I just always hold a knife in my hand like that."

The proper thing to do here if you really wanted to ask her out on a date is not to do it. There's plenty of other women out there you can meet in a more appropriate setting. There is no acceptable reason to turn a job interview into a date request.