I believe we can have what we ask of God. I believe the teaching of scripture in this matter is straight forward and simple. It is in aligning a reality in which we don't always get what we pray for with that teaching that a difficulty emerges. I think that is especially true when we're convinced that our request was agreeable to God's will and we thought we asked in faith without doubting. Yet, even in those apparent conditions, some prayer goes unanswered. "Sup with that!
First, let me say that our experience here was never meant to encapsulate all that has been earned by Christ and promised to us. Immortality cannot be inherited by mortality. Oh, the blessings are our's all right, bought with the price of blood (sale complete, I might add), but they are not necessarily experienced in the here and now. The tank of God's blessings is full, but we only get the splashover here and now. That's nothing to sneeze at--no mere trifle by any stretch. The tank includes eternal, disease-free, curse-free life in which we know even as we are known. Even some fraction of that looks like a lot to me! A lot more than many folks seem to settle for.
People have asked me how I can believe I'm going to get what I ask for when there have been times when my prayers haven't been answered, or at least haven't been answered yet. When I see the awesome quality and quantity that has been established for us in Christ, I just can't get hung up on what went wrong with yesterday's unanswered prayer, I concentrate on today's problems and today's prayers. Today's promise is always, "Ask what you will..." and "with God, nothing is impossible," so why let yesterday's doubt, yesterday's weakness, or yesterday's sin rob me of God's blessing today?
When I was studying accounting, oh, so many years ago, we were taught a concept called Zero Based Budgeting. The salient feature in that system is that there is no carry over from prior period's experience in producing the next period's budget. You start with a blank slate. I approach prayer everyday from a zero based outlook. Yesterday's failures in prayer have no effect on today's promises. So, I pray expectantly, and anticipate answers, and I get more than a few, for even though I've been known to to fail in a promise, Jesus never has!