What happens when you mess up a heart event in Harvest Moon DS?

Answer 1

This is one of my most favorite game series, too, so first of all . . . don't panic. I'm not sure what you meant by "messed up," but the likelihood is that it will be okay.

If you gave so many gifts that the heart color is past what you need to see the event (for example heart is at green, but you should have triggered the event at blue), then usually it will trigger anyway under the right circumstances. At the worst case, you can give them "bad" gifts until the color is right again and you see the event. Just don't progress too much further until you get to see the event.

If you accidentally gave the wrong response during an event, it still doesn't mean you can't marry them. You just don't get the extra heart points for that event.