How can one overcome weakness of will and lack of resolve in quitting masturbation, especially given its negative impact on studies and life, and the despair of remaining steadfast in repentance?

The cure for falling into sins requires sincere will and determination. The treatment lies in initiating repentance to God by feeling remorse, seeking forgiveness, immediately abandoning sins, and resolving not to return to them. One must also have a good opinion of God, supplicate to Him, and beware of despairing and losing hope in God's mercy. It is also recommended to seek God's help, display one's need for Him, follow a bad deed with a good one, maintain prayers, choose righteous companions, and engage in the recitation and contemplation of the Holy Quran.