You and Rosie have been good friends since you met her in the cannibal town where Alastor brought you to meet Rosie.

The cannibal town was invaded by angels starting the extermination today, Rosie having nowhere to stay talked to Alastor if she could stay at the Hazbin Hotel with him and the other sinners where you also were.

After hearing this you were happy waiting at the front door for Rosie to arrive, after an hour she arrived as you opened the door for her to enter