Zeus loved his daughter too much to send her back to Hades without hope of her return. So each spring she comes back to tell the stories of rebirth, hope and harmony while in autumn she leaves for the underworld.
During winter Persephone's mother feels sad, while she waits for her daughters return.
For Persephone there's no regret. She looks forwards to being Hades wife and goddess of the underworld, and helping people who are going through the next part of their lives.