Is the continuous belief that one's destiny is Hellfire, and the inability to imagine oneself in Paradise, despite performing acts of obedience and religious duties, considered having a bad assumption about Allah, and does this belief affect one's true destiny?

The believer must strive to obey his Lord, have a good opinion of Him, and fear his sins, in order to remove the feeling of despair from Allah’s mercy, which is one of the major sins. Fear and hope must be balanced. If he does good, let him praise Allah and ask Him of His bounty. If he does evil, let him seek Allah’s forgiveness. Despair of Allah’s mercy is disbelief if a person believes that Allah is unable to have mercy on him. Feeling safe from Allah’s plan and indulging in sins, relying on forgiveness, is disbelief or a major sin. To get rid of this feeling, one must know the vastness of Allah’s mercy and read the texts of hope, and Allah’s grace and mercy. Fear should be a motivator to perform duties and abstain from prohibitions.