This is an excellent topic and just the perfect place to post it. I enjoyed reading your thoughts on this!

I'd be a lot happier buying a house or anything from someone like yourself with integrity and a sense of responsibility. I like that you would want to be sure that you didn't pass on a lemon to someone else.
I am not afraid of spirit...well better put, I haven't thus far encountered anything that I feel is evil or dangerous...not that I don't feel fear when something looks intimidating or powerful to me. And not that I've had a wide range of experience because I haven't. I haven't visited a known haunted house (and I'd probably be scared if I slept over in one). I've experienced lots of spiders in the etheric and I am afraid of them, though I believe I create them, or draw them to me, or even colour them as scary because of my own fear.
I would not want to buy a house in which someone had been murdered. I am open-minded, but if there are x-amount of houses to choose from I'd much rather choose one where no massive terror was experienced. This stuff hangs there or remains there, even if it is covered up with good stuff, or so I believe. Like on
America's Psychic Challenge (which I loved watching!), where the psychics visited the hotel room where Janis Joplin died over 40 years ago and some of them could still feel the unpleasantness of it. It might be whatever a person chooses to tap into though. They might feel the despair, or the pain, or maybe even the sense of peace the spirit felt once they passed, if that were the case.
Having said that, I don't think you can erase what has happened as
feelings upon the environment, but if there is a malevolent
presence in a house, that would be a different story.
Ah, but that reminds me of an episode I saw of
Lisa Williams (I love Lisa! And true, I do watch a lot of reality TV

) where a girl sensed a scary presence in her house that turned out to be her mother's step father. He was a policeman and rather gruff in life - authoritative perhaps, and his spirit put off that type of energy which was interpreted as scary. So I feel open to the idea that what is scary might not be so scary once you know more about it.

But you know I always take this side of the argument that there is nothing to fear.
Okay, finally onto the point of the post, the question:
What do you suppose you would you do?I would seek out help spiritually within myself (my guides and spirit friends). Then I would see what was up and if it could be moved along (scat!). Then I would continue to live there. If I could not remove it, I would sell. I'd tell prospective buyers (after they looked at the house) that I think there is something there. If they are the type that don't believe, then they'd probably buy anyway. If they do believe, then I would probably not get a sale. Maybe like hotels do (as seen on reality TV), I'd make it a point of sale that the place is haunted (

Haunted House for Sale!

) as there are so many people eager to interact with spirit these days, even the scary stuff.