Hello and thank you for allowing me the opportunity to assist you.
In a worst case scenario, you can be sued for breach of contract (as you suggested), and the buyer could demand specific performance. In plain English, this means that the buyer could ask the court to order you to sell the house. Specific performance is allowed in real estate
contract cases because real estate is unique ... in other words, the buyer cannot buy a duplicate of your property like he could a car if you were to breach a sales contract for a car. So, the worst case scenario is a lawsuit for specific performance.
Having said that, my guess is that it is highly unlikely that you would be sued for specific performance. First, the buyer would have to pay his own attorney's fees (which would likely cost him several thousand dollars), and second, most buyers do not want to deal with that kind of headache. They just want to buy a house and get on with life.
If you have an agent, however, then the agent could theoretically sue you for the lost commission. I would consider this more likely than getting sued by the buyer.
Does that answer your question? Please let me know if you need clarification, as I am happy to continue helping you until you are satisfied. Also, your positive feedback is much appreciated.
Thank you for using our service!