Haha, " I will eat your heart" sounds unpleasant. I think any kid who heard thay will also get scared, even adult think so too, lol.

Anyways that heart shaped cookies really looks good. You know you can wrap them in a plastic or maybe paper wrapper then put a cute label and design on it and kids would love to buy that (ﾉﾟ0ﾟ)ﾉ→ it looks really good. It can be paired with hot choco drink or milk drink.