This is really good. I´m not the biggest fan of Ron, even less of the Ron/Hermione ship, because it just seems so unlikely to happen. BUT..you wrote it very well. It seems real and possible.
About the story in general - it´s easily read, there´s the ambiance...It has all that it should have, being a short story, and I really liked it. Didn´t even notice any grammar faux pas or spelling mistakes. That is a bit rare in fan fiction.
I would like to know more of the story though - a sequel would be nice, or added chapters. Did they stay together? Or not? Did she restore his memory some time later? Did they get back together? What about Harry and all this? I´m not really curious about the girl who taught Hermione, but two or three lines somewhere in a sequel or so would be appreciated - loose ends and all that.
Overall, i´d say you get 10 out of ten for this and a bunch of readers thirsty for more.
Hope you keep writing:)