The degree to which you are certain about anything is the degree to which you are bound by that certainty. Certainty is a commitment which you are unwilling to break. It is an act of will which governs your experience absolutely.
If you are certain that you are not in the Kingdom of Heaven, your certainty will blind you to It, even though it will not change the fact that you are smack dab in the middle of It. And because the Kingdom of Heaven does not operate according to the "rules" established by your certainty, you will stub your toe against It, trip over It, bump into It, and generally bumble your way through It - concluding that you are in a hostile environment.
Problems are not the evidence of karma or upbringing, but of current clumsiness occasioned by ignorance you are holding to with commitment. Likewise, healing of problems occurs not by overcoming your past, but by abandoning faulty certainties in the present, to which you are passionately holding on.
Awakening begins when uncertainty creeps into the picture and the strength of your certainty begins to weaken. This weakening feels disastrous, increasing your sense of vulnerability, since you have used certainty as a defense against the perceived unpredictability of the Kingdom of Heaven caused by Its complete disregard of the "rules" your certainty has set in place.
Uncertainty, embraced, allows you to genuinely "look again" with the eyes of innocence. Uncertainty, embraced, is an act of Love. Uncertainty, embraced, is not an act of will, but of willingness to recognize that which is Real in each and every thing. It is the antidote for certainty.