Does God Almighty forgive all sins, especially taking a life, even while striving to save another, and is that considered freeing a slave (emancipation) which atones for taking a life, and does God forgive not fasting Ramadan in childhood due to incomplete awareness, and what is my real problem, is it weakness in faith or a psychological illness, and how do I find forgiveness from God?

Sincere repentance erases sins and makes the repentant person as if they had no sin. Intense fear of Allah, regret over sins, weeping out of His awe, and loving uprightness are good signs that must be followed by performing good deeds, abandoning evil deeds, and not despairing of Allah's mercy. For Allah forgives all sins for whoever repents to Him sincerely, as stated in the Holy Quran and the Hadith (definition) Qudsi, and His mercy and forgiveness are greater than any sin. The true Muslim combines fear and hope, hoping for Allah's mercy and fearing His punishment. It is recommended to frequently remember Allah and accompany righteous women, and delayed marriage might be a punishment from Allah.