Flannery O'Connor's Wise Blood can be considered a hopeful book for its underlying focus on redemption. Hazel Motes lives by a certain sense of nihilism that seemingly contradicts this focus on redemption; however, his eventual acceptance that he truly desires a connection with Jesus make the hopeful elements of the novel a valid discussion point.
Hazel Motes, the protagonist of the novel, has a very individualistic view of Christianity, much like the view Flannery O'Connor herself holds of Christianity. Like O'Connor, whose short stories and novels can be described as works of Christian realism adorned with a witty touch and an honesty that verges on the grotesque, Motes rejects the groupthink approach to a relationship with God and Jesus that characterizes most Christians in search of redemption in the American South. Thanks to his deeply personal and individualized view on faith, Motes is true to himself, which is an essentially optimistic approach to life; nihilists find everything to be meaningless, so perhaps the hopefulness O'Connor mentions exists in Motes's inability to find his own desires, which change throughout the novel, utterly meaningless despite his nihilistic predilictions.
A hopeful view that incorporates faith in God more directly can also be explored. Perhaps O'Connor believes that God is at work in Motes's life, throughout his entire life, whether he desires it or not, which could explain why Motes eventually accepts the reality that he does truly desire redemption. After all, as a young person, Motes was ready to commit his life to being a preacher, but his experiences in the war may have left him with an emptiness as a result of trauma; post-combat stress often results in faithlessness and a sense of meaninglessness, so it makes perfect sense that the message Motes prefers to preach is one of peace.
Hazel Motes is a character full of internal conflict, both psychological and spiritual, and the fact that conflict even exists is in fact hopeful. His church without Jesus is still a sacred place, which suggests that meaning is important to Motes despite his conversion to nihilism. O'Connor's insistence that her novel is hopeful is not unfounded, just unexpected.