There are two things, self-esteem and not giving up. Self esteem, for the most part, is the recognition that you are inherently valuable. With or without successful dating, with or without bitachon, and with or without finding the right person.
Bitachon is about trusting hashem (emuna is belief). One can philosophically question whether one’s preconceived ideal results should figure into their bitachon. I believe that they should, particularly when one has a desire based on what they perceive to be a spiritual goal. Getting married falls into that category.
Communication with God and acceptance of His judgment are also a big part of this equation. God is purely good and His actions are purely good – whether you see that or not. But you can ask Him to change things, particularly if there’s an element of His sake involved (like Chana’s prayer).
Bottom line- self esteem does not equal the belief that you WILL get married. It equals the belief that you ARE important. As you ARE. Getting married is good. God is perfect.
May you merit to see the good in things – particularly yourself – throughout the rest of your life.