Confidence comes from knowing what's true about your body and what turns you on. That comes from education and from practice.
Important caveat: What's true about your body will be different from what's true about your partner's body. Neither person is "right" or "wrong"; we're just all different. There are as many types of sexual expression as there are humans alive on earth, and confidence comes from knowing what happens to be true about our own individual sexuality.
Your partner's confidence is just as important as your own. You want to communicate honestly and openly about what you like, what you want, and what you'd like to try—or not try. And if you're afraid that, in being honest, you might hurt your partner's feelings or make them feel insecure or defensive...you'll hesitate to say anything. You may even hide your desires.
Worst of all is when an insecure partner judges a woman for wanting or liking what she wants and likes, for doing the things she's done, or for having the thoughts and feelings she has.
A couple's ability to appreciate each other's bodies and sexualities and welcome them as they are is at the core of all the first three things women want. Mutual acceptance creates a context that facilitates pleasure, that lets you turn off the brakes, that makes you feel worshipped.
That's why the last thing women want is: