I love this poem, but perhaps I read it a bit more “darkling” than others do. It’s a poem of hope but what makes the hope credible and unsentimental to me is that the poem grants so much truth to despair. Despair does get the final word, and the end is shocking that way. Even the earlier stanzas’ talk of being desolate and fervorless does not quite prepare us for the despair of the ending, for being absolutely unaware of any cause for hope. I think if the poem were prose (a passage, say, in an inauguration address!), it would clearly be an affirmation of hope (“there trembled through his happy good-night air some blessed Hope, whereof he knew and I was unaware …”). But I think the line breaks inevitably give an added emphasis to the final line that doesn’t erase the hope but does make it absolutely unsentimental.