That's what I was going to say. Even if GE is feeling some doubts, it was still an incredibly rude statement from a friend. Besides don't like 98% of people getting ready to get married have some slight doubts at least? Like "am I making the right decision?" is probably a normal question brides/grooms ask themselves.

Whether or not she's feeling any insecurity about the relationship, to me, is entirely separate from this statement being incredibly rude and insensitive and just inappropriate. I mean, "I hope it works out" to me seems to insinuate that you think it won't. A real friend would say "I wish you every happiness" even if they were concerned, rather than a statement that sort of passively aggressively hints at their pessimistic view of the relationship. "I wish you every happiness" means you wish the relationship success, without hinting that you personally feel it's good or bad.

This could just be a matter of a friend having no clue how she sounds or what words are coming out of her mouth, but I'm glad you stood up for yourself and pointed out to her that you felt hurt by the statement.