When you try to simplify things for yourself but find it impossible to do so, things have already been simplified for you.This passage appears in the context of a story about a renowned mourner whose actual mourning is blatantly hypocritical, being all show. This upsets Confucius's disciple Yan Hui to no end. How can he have such a reputation given this hypocrisy? The real Confucius would, of course, share Yan's distress, but Zhuangzi's Confucius is almost always able to see through to the Daoist point of view, even if he cannot realize it.
(Zhuangzi, 6:48; Ziporyn)
The turning word in this sentence is "impossible". We try to understand life and death, but we cannot. We want to know Why?, but we cannot. We hunger for answers, but there are none. From the Daoist point of view, this realization is to be hoped for; the alternative is to either spend our lives in the endless and vain pursuit of answers, or to attach to answers which fail to truly satisfy.
This ‘insincere’ mourner has not allowed the impossibility of knowing to cast him into despair, however. Rather, Confucius tells us that "he has gone to the very end of the matter, beyond merely understanding it." In other words, like a Daoist, he has taken the utter unknowability of things as an opportunity to abandon the senseless and distressing pursuit of answers and has instead "handed it all over to the unavoidable." Suddenly, it is all "already simplified for you." However things unfold, whatever happens, whatever Reality might 'be', all is well. Why? By virtue of being Reality.
Which brings us to Trust. We are given a choice, entrust ourselves to the Unencompassable Transforming, or despair. Is there 'faith' here? Is it a belief, a mental conjecture grasped, that "all is well"? Possibly, but perhaps not necessarily. The "wellness" of Reality is utterly non-contingent; it depends on nothing. Every possible Reality is Good. A completely 'materialist' Reality is Good. Yes, even a Reality of heavens and hells, absurd as it may seem to us, if it is, is Good. In the end, Trust is also Surrender. Sweet Surrender. Why sweet? Because it feels so good. Why does it feel good? Because everything is already simplified for us; the belt fits perfectly. What belt? Exactly.
You can check out Scott's writings on Zhuangzi here.