I think you have "confident" and "cocky" mixed up here. A confident person has dimension, doubts, and can definitely say they're uncertain, but they also have no problem saying it when it applies, whether it be to a person or a group. A cocky guy knows everything, is everything, and never backs down, no matter how wrong he may be.
You say you're a shut in, so I think you might be very lacking in social experience to determine the difference between the two. Cocky guys get women, sure, but they can't hold onto a woman. Confident guys also get women, but they have no problem keeping the women they want. (and want them)