The Chovos Ha’Levovos explains that the foundation of bitachon is knowing that HASHEM looks out for my interests more than I do. That HASHEM is more concerned for my good than I am. And that HASHEM loves me more than I love myself.
This is also the basis for teshuva. Once I accept that I am human and that HASHEM knows that, I can live with the fact that I will fail. But HASHEM, in his infinite love, gave us a way of undoing the damage that we have done.