Need help please, what is the best way to protect myself being sued by buyer?

[Chelsy C]

Its my first deal, after a lot of issues and struggle, it finally under contract.
Today the buyer come back and asked a lot of repairs to be done it is the condition of removing the inspection contingency. And the appraisal price came back $11k less than contracted price. The worse, I am now worrying the liability issue of buying may file law suit later on.

Here is why I concerned, I repaired a small crack in the foundation, this crack was suspected to have water leak inside of the previous laundry room(which we changed it to an office). The next door neighbor told me he knew the previous owner told them that there was water intrusion to that area. When I asked my listing agent, she told me it's ok not to mentioned it, since it's only someone told me, and I didn't see it. Would that be an issue from your experience?

Also what is the best way to protect ourselves being sued? and how likely a buyer will sue the seller?