I don't know if someone has posted this quote already, but Rowling has confirmed that it indeed will be Ron and Hermione:
It’s done, isn’t it? We know. Yes, we do now know that it's Ron and Hermione.
Just to rule out any doubt 🙂
i know! ron says something like i love u hermione then hermione turns pink and says dont let lavendar hear u say that then ron says i hope she did or something like that and please dont tell me something stupid like she was doing his hwrk b/c that was love too and jkr is a good author like that. sooo... 😗