How can a woman repent and atone for her sins, free herself from attachment to a young man, from immodest display (tabarruj), and from jealousy, after committing many immoral acts and abandoning the hijab, given her desire to return to God?

You must repent sincerely from fornication and displaying one's adornments (tabarruj). Wearing the hijab is a good deed. The soul's inclination towards tabarruj is among the whispers of Satan that must be resisted by seeking refuge (with Allah) and remembering the warnings against those who display their adornments. You must frequently supplicate to Allah for steadfastness and firmness upon the truth. A relationship between a man and a woman who are not mahram is not permissible, therefore, you must cut off ties with the young man. If he repents and turns to Allah, and you wish to marry him, then supplicate to Allah to facilitate that for you. It is not permissible to seek emigration to disbelieving lands except within narrow limits. If the young man does not wish to marry or does not repent, do not distress yourself over him, for Allah may provide you with someone better than him. Forgetting the young man is easy if your intention with Allah is sincere, and there are matters that help in treating infatuation.