Hosts cook, staff, and say no to other people because you said you would come. Flaking is not a casual city habit here. It is a hole in a small room.
If you must cancel
Do it the minute you know — not the morning of, not in the cab going the other way. Use the listing channel. One message with the reason. Then read refunds instead of bargaining in five paragraphs.
Bad reasons
A better party appeared. You got nervous. Your friend bailed so you bailed. Weather you already knew about. Those are how you stop getting yes.
Good guest insurance
Put it in the calendar. Set two alarms. Arrange the ride the day you pay. Tell a friend who will bully you out the door.
Apply on experiences only when the date is real. Curiosity is cheap. A yes is not.