Does repenting from zina (without engaging in sexual intercourse) prevent marriage or entering Paradise, especially after he informed his former fiancée, who insisted on forgiving the other girl, but the girl refused forgiveness and marriage?

The questioner is congratulated on his repentance, and repentance erases what came before it. He should have concealed himself and not told anyone about his relationship with the girl. The questioner erred by showing the girl's picture to someone who wanted to marry her, and his greater error was keeping her picture, which indicates the insincerity of his repentance. He must destroy the picture and repent to Allah for exposing the girl, especially if she has repented. It is hoped that no harm will befall him from her supplication as long as he has sincerely repented and asked for her forgiveness.