His heart is good

II Samuel 12.20-22
David got up from the floor, washed his face and combed his hair, put on a fresh change of clothes, then went into the sanctuary and worshiped. Then he came home and asked for something to eat. They set it before him and he ate. His servants asked him, "What's going on with you? While the child was alive you fasted and wept and stayed up all night. Now that he's dead, you get up and eat." "While the child was alive," he said, "I fasted and wept, thinking God might have mercy on me and the child would live."
When I want something I often don't ask, not because I don't think it's valid but I doubt that the one I'm asking loves me enough to give it or to change their course simply because I am asking. David knew that God abounded in lovingkindess, that He was good to those who didn't deserve it, and moreover that He loved David specifically. Therefore David, even though he knew he had sinned, asked. And when God still said no he worshiped.
When I say, "Your will be done", do I really believe His will is the best? and for my good? If indeed I believe His heart is good, personally for me, then I will ask--believing that what He chooses will be the very best.