I believe that your friend knows what she wants, she knows what she needs to do, she has already taken her decision, but she seems to be scared to go ahead. she is scared of ' what will people say'. she is scared for the reoutation. But i would advise her to be strong. it is better to break up an engagement rather than getting married, and then seeked divorce.

It would never occur to me to come to a forum and ask advice for a "friend".

I think this is you who is needing to break off an engagement

I know that a lot of people feel humiliation due to failed relationships, I guess I don't understand why anyone would feel humiliated over making the "right" decision in their lives. If she knows that she won't be happy in her marriage to this guy then why would she even hesitate and consider marrying him anyway? Seems pretty ridiculous when your on the outside looking in.