How can one get rid of many sins, such as lying and fabricating stories, and the fear of God's unforgiveness?

If you desire sincere repentance, its door is open, and Allah accepts repentance. Seek Allah's help, and supplicate frequently so that Allah may turn your heart to His obedience, make faith beloved to you, and make disbelief and disobedience detested by you. Remember the warning against disobedient ones, for lying leads to immorality and then to the Fire, as stated in Ibn Mas'ud's hadith. Truthfulness is great and a cause of happiness in this world and the Hereafter, whereas lying destroys its perpetrator. Allah has commanded us to be with the truthful, and He has divided creation into the blessed (people of truthfulness) and the wretched (people of lying). Truthfulness is the messenger and spirit of faith, while lying is the messenger of disbelief and hypocrisy. Lying and faith do not coexist. Renew your covenant with Allah, associate with righteous women, and frequently remember Allah and recite the Qur'an, for Allah forgives all sins.