Andrew has given you an excellent response and I agree with all his sage advice.
Unfortunately, there is a wide range of interpretation among Rover sitters about what constitutes house sitting. Some will move in, but also do drop-ins and walks for other dogs using your home as a base of operation. Others may only be there from 7 pm to 7 am and have regular full-time jobs. Some will check in on the dog in the middle of the day; some may charge you extra for a drop-in visit or walk. So it is always good to go over your expectations with the potential sitter.
Rover only states that: "House Sitting: Sitters watch your dog overnight in your home."
https://support.rover.com/hc/en-us/arti…
and each "night" is good for up to 24 hours of care.
https://support.rover.com/hc/en-us/arti…
IMO true house sitting is a premium-type service and customers should expect to pay a premium fee for someone staying over at their home and providing that level of security and care for the absent owner.
Sherry, you are absolutely right to question how this sitter is planning to fulfill this job and, if it is not what you want, then cancel it and find yourself another sitter. But be sure to interview several sitters and find the one who can provide what you want and need.