Hopefulness is a pleasant feeling which is resulted from faith and cognition towards the origin of the universe. This valuable gift leads man towards worldly bliss and eternal optimal perfection. However, human of the current era, despite his victories upon natural resources, is always afraid of future and life-related issues. Even in religious societies some persons suffer from hopelessness (disappointment) due to neglecting Islam's valuable treasures. Thus, the present article, by reviewing verses and narratives in brief, tries to express the effects of hopefulness and trust in God on the individual's happiness and bliss in the world and the hereafter. According to the principle of priority of prevention over treatment, by considering these effects one may prevent hopelessness outbreak and maintain and reinforce hopefulness in oneself. Effects of hopefulness have been reviewed in this article. Hopefulness is a motivation for human's movement and effort, returning towards God, achieving life's goal, thanksgiving, facing the problems, task-orientation, achieving success, resistance against harmful fears, and preventing spiritual crises and depression. In addition, factors of reaching hopefulness, including faith in God and intercession of saints, waiting for the Savior, conformity between wishes and reality, and loving and serving mankind, have been addressed.