@Sean375
Other hosts have given great advice about the tenancy concern so you should definitely look into that.
On a different note just to share my experience from hosting longer-staying guests, a person just visiting and staying a few nights or up to a week vs. someone "living" in your home for several weeks and even over a month are very different. The guests will have very different needs and expectations.
If you are thinking of hosting guests longer than 3 weeks, you should investigate and know what the going monthly rate is to rent a room with a 1 yr rental contract in a roommate situation. Your monthly payout total should be at least 20~30% more since you won't be getting a deposit of the first and last months' rent. I've had a few potential guests ask for additional discounts and my response was always...... something along the lines of "It seems you have no idea what a typical room rental in an home like mine would cost in Seoul 🙂 I suggest you should do your homework about rental prices before sending messages like this to potential hosts. I guess we can both agree that my listing is not in you budget so it seems we will not be a good fit. Good luck finding a place that better meets your needs!"
If you are interested in longer-staying guests I'd also suggest you may want to consider it for international guests only. Maybe an exchange student or someone participating in some sort of exchange program or training program? - this is actually what I do. If you need ideas about longer stays and how to manage them, feel free to take a look at my listing description 🙂
Good luck~