The green and gold ring was a gift from Tinker Bell. At the end of their “date” she takes a curl of her hair and a scrap from her dress and poofs it into a ring.
"Anytime you think you can’t smile or laugh, any time you need hope, wear this ring and know that there is someone that cares about you. No matter what happens or where I am, Regina."
She can’t wear Daniel’s ring because it hurts too much. She wears Tink’s ring because some days it is the only way she can remember to have hope.