I don't get the impression that a kiss from anyone would have worked, not naming 'a person' was just building suspense! His instinctive reaction is then "I told you, no kissing!"

the fact that Hermione tried it at all implies that she loves him (otherwise she wouldn't've expected it to work

The relevant belief for Hermione to have as I see it is he loves her. Hermione knows enough about the way dementors and patronuses work to realise that his emotions are what matter. Whether she is feeling it too, so to speak, is irrelevant. Although of course we know she is. :)