Will Allah accept the repentance of an adult girl who regrets practicing cybersex with a young man, and who, after he left her, felt that she had lost trust in herself and in others, and will Allah accept her supplications against him?

You have wronged yourself and incurred Allah's displeasure with these sins. You must offer sincere repentance and conceal your faults, for the door of repentance is open, and Allah will accept your repentance if you are truthful in it. Allah Almighty says: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" Strive in seeking forgiveness, and increase in supererogatory prayers, remembrance (dhikr), and reading the Quran. Keep company with righteous women, and begin a new chapter with your Lord. As for this person, he is exposed to a severe warning if he does not repent, and neither of you bears the sin of the other; both of you have wronged yourselves. Your supplication against him is an injustice because it was with your consent.