Will a woman be held accountable for her inner feelings toward a non-mahram man, and how can she know that Allah has forgiven her and accepted her repentance, and how can she strengthen herself in obedience and drawing closer to her Lord?

May Allah accept your repentance and help you persevere upon it. Rejoice in the acceptance of your repentance if you are sincere in it. As for the feeling you experience, you will not be held accountable for it as long as it does not translate into forbidden words or actions. It is stated in the Hadith: "Indeed, Allah has pardoned for my Ummah that which they whisper to themselves, as long as they do not speak of it or act upon it."

Have a good opinion of Allah and draw closer to Him through righteous deeds. Drawing closer to Him is achieved by increasing voluntary acts of worship after performing the obligatory ones. You must strive against your soul, try to forget this man, and abandon any hope concerning him.