What should I do, given that I prayed Istikhara twice concerning my engagement to a person, and the first time I felt unease and distress, while the second time I felt comfort and love for him?

If a man whose religious commitment and character you approve of proposes to you, seek Allah’s guidance (perform Istikhara (definition)) regarding him. If the marriage is facilitated, then rely on Allah. Otherwise, look for someone else, while making abundant supplications. It must be noted that it is not permissible for an emotional relationship to exist between a man and a woman who are not married to each other. The fiancé is considered a stranger to his fiancée, so it is not permissible for him to be alone with her or to talk to her except out of necessity.