It is not about "believing you are the best version of yourself" that makes it work; it is "being the best version of yourself".
Sometimes I meet a woman and we seem to click, this is rare. If they are single (they usually mention a bf if they have one), most of the time I try to arrange a time to meet so we can grab coffee/study or something. I get stood up/rejected just about every time. Usually these are women who seemed to really like me in person. Hell it even happened when a girl ASKED ME out! They stay friendly, but have no romantic interest.
You are probably acting needy/relationship-type as soon as she seems to like you or you feel that you click. No. Don't change your behavior like that just because you "want this girl more than the others" Same game, teasing, push pull, being confident, leading, being non-needy, not-desperate. I can identify this as your problem because I used to do this shit starting out. I would idealize and put some girls on a pedestal because she is a "10" and be extremely cool and aloof with 5s and 6s. What changed? Nothing. She is a woman. Her beauty shouldn't affect how you game.
However after 3 years, my desire to even try has almost entirely eroded. Maybe my mind is playing tricks on me now, but it seems that whenever I meet/talk to a girl, I can sense the disinterest from their tone. The conversation will be me trying to get to know them and rarely will they even feel compelled to ask me anything.
Who tries to get to know a woman he just met instead of leaning back, relaxing, and enjoying the interaction without even asking her name? Someone needy :) Someone getting into relationship behavior. You GET TO KNOW THEM once it is sure that she is attracted to you, in the comfort phase as Mystery coined it. And not with "tell me your life story", with games and fun questions. Don't worry, she will tell.
Your problem seems to be neediness, and the fix is easy. Get girls and you won't be needy anymore. "How do I get girls in order to get girls?" You may ask, and that would make sense.
Act like you need nobody else. At peace with yourself. You don't need any external factors to be happy. I'm sure you have had this mental state for a few times in your life. Try to remember how it felt. And relive that moment.
When you are content to be simply yourself and don't compare or compete, everyone will respect you.