you're positive you've seen all the heart events? there's a green one too, so that makes 5.
Oh? I was under the impression that I couldn't see any of the green heart events until I had confessed and started dating, which is how the previous SOS games worked. I was reading stuff about being able to get the pendant and confess your love after getting to a blue flower and seeing all of the events up until then. If this isn't the case however, that would be great! I'll try unlocking the first green heart event now. :D