The poem "Hope" is an antithesis. It actually is about how Hope can be cruel at times and simply flies you by when you need it the most. In itself, it is a sad and kind of cruel poem because it presents Hope as a "timid friend."
Bronte makes an allegorical notation to hopelessness when she mentions the phrase, "She sat without the grated den". A "grated den" is the place where animals would be placed before a savage show in ancient Rome. It is also associated with the place in which Daniel was incarcerated with lions (which he defeated).
Hence, we can assume that what Bronte means to say is that Hope can be cruel. We watch her losing her battles to fate, and hope, like a cruel enemy, decides to simply keep moving and abandon the speaker. Hope is cruel enough without even needing a grated den of beasts to devour the writer alive. Hope's coldness and lack of support were murderous enough for her.
In this ironically cynical poem, Emily Bronte expresses the failure hope had in giving her joy. Hope is supposed to inspire because it is the feeling one has in expectation of something, usually a positive outcome. Bronte personifies the sentiment by using a capital and by referring to it as a friend. The personification is extended throughout the poem. Because Hope abandoned her, the speaker remained uninspired and unhappy.
In the first stanza, the speaker states that hope was ‘but a timid friend.’ It is quite ironic that she refers to Hope as a friend when, in fact, the content makes it obvious that it wasn't a friend to her at all. The word 'timid' suggests a lack of courage and ‘but’ assumes the opposite. The speaker is evidently referring to a situation in which she was trapped. This could have been physical (such as in a cell) or metaphoric (as in a situation). The speaker desired a better outcome, possibly freedom from the entrapment, but there was none. The speaker’s expectation was quashed and she was not saved. Furthermore, it appeared as if Hope was there, just observing her as someone who has only their own interests to consider would.
In the second stanza, the speaker sees Hope’s lack of support as a fear. This links with ‘timid’ in stanza one. The speaker sees this as cruel for she sought help and it was not forthcoming. She knew it was there, but it turned from her.
The simile in stanza three intimates that Hope was not sincere for it was standing watch, but it was a purposeless exercise since Hope is supposed to bring help and provide sustenance to an expectation. Hope, in this instance, seemed to take pleasure in the speaker’s strife by suggesting that she be at peace (when there obviously was none to be had) and singing when the speaker was overwhelmed with sadness. When the speaker listened to her, Hope would stop her tune. The implication is that Hope was the speaker’s greatest torment. The speaker’s realization that there was Hope but that it was not forthcoming was devastating.
In this regard, then, the speaker states that Hope was ‘false’ and ‘unrelenting,’ implying that it had no substance and would not bring relief although it was still present. In another personification (apostrophe), the speaker refers to Sorrow as seeing the final relics of her happiness being strewn around. The speaker felt profoundly abandoned and utterly helpless. Grief, though, brought at least some relief. These lines emphasize the depths of despair to which the speaker had sunk. All that she had left were broken memories of past pleasures. In her distress, the thought of these overwhelmed her with sadness.
The final stanza accentuates the speaker’s resentment for hope having abandoned her. She feels that even hope’s smallest gift would have soothed her intense pain, but it left her and never came back. The contrast between her being trapped in misery while Hope is free and able to soar further emphasizes the absolute anguish that she has been through.
The mood of the poem is overwhelmingly sad and the tone is depressing. It probably depicts a period of overwhelming despair when all seemed lost and even hope, usually one's last resort, was absent and couldn't be relied upon. Such utterly overpowering despondency is rare and one can only feel pity for the speaker for having suffered it—and simultaneously express admiration for (one presumes) having defeated it.