I'll admit I am not the most confident person always, but even when I'm feeling very alpha-ish, I don't think anyone can tell. Even when I am confident, others still see me as insecure.

How do you convey your internal attitude accurately to women?

Have a look here, J Slay explains a lot about body language. 70% of what you represent goes through your body and not what you say.

That's exactly what I was going to say. Your body speaks more than you can ever imagine. Body language is the key. Check some alpha positions, I call that ABD (Alpha Body Language). Just consider these three main factors: Keep your back straight, your shoulders aligned with your back, and rise your chin just a little bit. When walking, do it slowly but freely. No one's running you 'cause you're alpha. Try it, at first your body's gonna ache, but you get used to it in a week.
Go for a stroll to the park or a mall, and by keeping that body language, check in the feedback in your surrounding. Not only women will look at you in a different way, but also will men do.