im repaying the kindness that raised me with obsession

I transmigrated into the body of an evil witch in a fairytale. While I was drowning in loneliness, hated by everyone, I happened to pick up and raise a pair of siblings who were eating my candy house... "Hazel the Witch, you're sentenced to execution for kidnapping!" Who would have known that I'd be falsely accused of kidnapping the Grand Duke's younger siblings! Thankfully, before she knew it, Hazel became a nanny in the Grand Duchy with the help of the children. However, her employer once said... "A Grand Duke doesn't marry witches. Nor nannies, of course." and gulped down kimchi soup. I don't have no intention of getting marrying either, you know? Especially not to you, your Grace! I'll just raise the kids and then quit!