Hypothetical

Maybe I should've been more clear: She's leaving you either way in this scenario.

Personally I've always seen any failed attempts at proposal to be a deal-breaker because it's sort of an irreconcilable difference. Obviously this isn't always the case but I've never seen anyone say no to a proposal one day and then stay with the person for years afterward.

Guy I worked with had been living with the same girl for years. He really wanted to get married. She didn't. She never left him, though, and he never gave her an ultimatum, and as far as I know they're still living happily ever after - with no ring.

And of course there's the more common scenario, which the other posters in the thread were thinking of, where she does like/love the guy, but doesn't feel they're quite ready for that ultimate step yet.

As for the original question, if he's <insert adjective here> enough to propose in public when he's not 100% certain she'll say yes, he deserves to get his rejection in public.