The CO asked me "What is his favorite color?" while looking at David's emails that are in pink, blue, green, purple, red as font colors. When I answered black, gray and yellow, he gave me that teasing smile as if he's saying "Hmmm... are you sure that's all?".
There's always one and ultimate question - sometimes more (like Ms. Universe winning question) that you will really have to sound convincing and sincere. Mine was "How sure are you that you will be the last wife?"

I was tempted to say "World peace! We need world peace!"
There's this one applicant before me who was asked "Why did you want to marry him? Don't tell me it's because you love me. What other reasons?" The girl said, "But I do love him, Sir" and she got rattled and tensed she was nearly in tears after the interview. If I was asked that question, I would have said "First, I really want to marry him because I love him, I really do. As for other reasons, it's because I have waited for so long for the right person to come into my life and I knew that he's the one."
Having said all these, you should be prepared for unexpected questions. If you really know your fiance/husband with all your heart, you will pass the interview with flying colors. Sure you'll be nervous... and the truth always comes out especially when your nervous.
--Mae