Given the choice, it's better to forgive than not. It's better to trust in the decency of humanity than not. It's better to love than not.
Maybe somebody doesn't fully deserve it. But if you choose to hold on to that bitterness and hurt then you'll be a worse person based on that choice. You'll be unhappy. You'll be dull.
So let go of all that. Choose to stay sweet and innocent and pure and lovely.