"Everything that our Lord has already appointed to do, it is His will that we pray for that, either in particular or in general" (Ch. 42). But how are we to know what He has already appointed to do? Since we have no idea about all that — and it is going to happen anyway, why bother to pray at all?
One of the important things that Julian's revelations taught her, and which she then teaches us in her book, is to learn to give up our defeatist outlook on ourselves. Yes, we have "to yearn", but we also have "to trust". Yearning and trusting then amazingly add up to acknowledging that we love God and that He has in fact loved us from "without beginning".
Once in a while we can look back and realize that something which we hadn't expected did in fact happen and that it was a good thing that it happened. It wasn't "chance": someone who had our best interests at heart gave us that lesson — both at the time and in the later realization. There is no need to puzzle over the "why thens" and "why laters". We have received a slow-motion lesson in trust.
And over the years we slowly trust more, but also yearn more, for “the nearer we are to our bliss, the more we must yearn”; and accept (if not understand intellectually) that part of our duty and our joy that is praise is to pray simply for what God has appointed to do, that doing God's will is indeed Love, His and ours.