Is the marriage of a young man who loved a girl and spoke with her over the internet halal or haram, and will that affect their future happiness?

Your marriage to the girl you met is permissible (halal), but you must repent to Allah for having exceeded the limits of the Sharia in speaking with her, for repentance erases what came before it. We advise you to stop speaking with this girl and be patient until you marry her if you are able. Otherwise, turn away from her and occupy yourself with what benefits you.