As a rule, desperation is a condition that implies an understanding of the complete hopelessness of a disastrous situation and the lack of prospects. Reliable is the condition of a person in which he sees for himself further opportunities and the likelihood of changing the situation in the best way for himself.
Many people interpret these conditions as strictly negative and positive and see something useful in hope, while despair is considered detrimental. It must be said that at first it is necessary to distinguish between understanding these terms, for example, despair is not equal to despondency, and hope is not equal to healthy optimism and the presence of inner confidence.
So, many people say do not despair even in the most hopeless situation. That is why (this is often shown in the movies, but it is probably observed in life sometimes) a person with legs torn off on the battlefield is said something like: “you will get out” or even “you will still dance”. Also, a primitive religious hope seems to me something similar, a way to reconcile a person with the inevitable misfortune, evil, to give any positive feelings.
In turn, despair can often give a sober look at the situation, and allows a person to really understand the situation and, if he is strong enough or lucky with people who can help in understanding this experience, then even sad situations will be passed worthy of a human level, without self-deception. Therefore, in despair there is a significant potential that needs to be understood, although the experience itself can be unpleasant.
In conclusion, I would like to note that this reasoning should not be seen one-sidedly, in the hope of too much positive, and despair in inept hands will bring only disastrous results, nevertheless, the world should not be considered primitively and within the framework of pleasant / unpleasant.