Is there anything that you will never know if others don't tell you?

A colleague of mine, who worked with him for three years, always thought she was a man. As a result, she told me at a dinner party three years later that she was a woman, which was completely unexpected to me. She is stronger than me, with short hair all the year round and invisible breasts. I was really blind for three years. I blush at the thought of telling her those dirty jokes.