those of us who know better we call that Faith failures or unbelieving believers because the word " believe " has been misused and misunderstood because it is more than just mental assent, you need to get the word deep inside of you as a seed which Jesus taught in the Parables of the sower to come to this place of being fully persuaded which is found in Romans 4:21. Not just persuaded but fully persuaded building the imagery of the word which is what causes faith and expectation to come into existence in your soul or heart. It's all part of Mind renewal. My condolences for the loss of your sister who's obviously in heaven. My mother who is born again just passed 2 weeks ago at the age of 96, my papa passed away 8 years ago at the age of 83 and my sister who was 51 13 years ago passed away all of them gloriously saved and in heaven. Divine Healing as well as Divine provision is a touchy subject because it has not been taught right and those who do teach it are not living it.