I'm possibly curious that this happened:
Vivzie didn't know which of them fell in love first, but this answered the question
Notice how Charlie looks shy while Vaggie looks grateful. Charlie and Vaggie hung out with each other, enjoying one another's company, and Vaggie feels like she can have a better life in Hell than she did in Heaven. She very much likely acts like Charlie's bodyguard, she wants to protect Charlie as a thank you for what she did. The bow Vaggie has is a gift from Charlie, it reflects on Vaggie's emotions and how she feels. Like when she's mad, they turn into horns shape.
I hope we get to know more about their relationship after Charlie found Vaggie