Jorah agreed to sell his speedboat to Dani for $20,000. Dani made an initial payment of $10,000, with the remainder of the purchase price to be paid when the speedboat was delivered. Before Jorah delivered the boat, he had it appraised and was surprised to find out that its market value was $30,000. He has as a result refused to deliver the boat to Dani unless she pays him an extra $10,000. Dani refuses to pay the extra amount and sues Jorah for breach of contract. She has asked the court to award her $20,000 in damages.

What are Danis Damages? Explain and support your answer

PLEASE ELABORATE FURTHER WITH A LEGAL PERSPECTIVE TAKING INTO ACCOUNT CONTRACTUAL LIABILITY