You are honest in all you do.

Don't know.

I've had the online and phone interview, and they asked me the same thing. I'm now scheduled for the in-person interview for .Net development tomorrow. They asked me this question, and my answers built upon themselves. Initially they asked something about how true my word is, and I said that my word is everything. When they asked me "How do you prove your honesty", I referred back to my what I said previously about my word, saying that I prove my honesty by being true to my word, and making sure that I do what I say I'm going to do.