Mary, a hardworking and industrious lady, lives in and does business in Canada. Due to her industry, she has bought several houses in Lang'ata, Nairobi, three of which she has been leasing to the Kenya Wildlife Services to house their senior managers. John, a young man with great ambitions, has always desired to purchase a house in Lang'ata, but had been unable to do so due to the high prices of property in Lang'ata and his inability to secure financing from banks and other financial institutions. John has learnt of Mary's ownership of the three houses being rented by KWS and has designs to purchase one of them by hook or crook. He sends Mary an email detailing the poor condition of one of the houses due to poor maintenance by the tenants, the KWS. He further states that the said house has been earmarked for demolition by the Kenya Airports Authority (KAA) for being in the flight path and posing a security risk to the planes at Wilson Airport. In the email, John offers to purchase the "condemned" house from Mary at Kshs. 7 million, way below the market price of the house, which was then valued at Kshs. 20 million. Mary questions the low asking price, but John tells her that property prices have considerably fallen in Nairobi due to the security threats posed by the terror group Al-Shabaab. Taking into account all the circumstances as per John's email, Mary agreed to sell the house to John at the proposed price and a Sale Agreement was prepared and signed by both parties, though the transfer documents had not yet been prepared. Mary came back into the country to complete the transactions, but her inspection of the house revealed that it had been perfectly maintained by the KWS and that it was in good condition. She also discovered that the house had not been condemned for demolition as was stated by John; and that the terror threats from Al-Shabaab have in no way led to the reduction in property prices in Nairobi. Based on her findings, Mary refused to sell the property to John and repudiated the Sale Agreement. Five years after Mary's repudiation of the Sale Agreement, John files a suit in court demanding for the specific performance of the Sale Agreement and the transfer of the house to him. John is, however, unwilling to pay the proper market price for the house, which has now appreciated to Kshs. 50 million, insisting on paying the previously agreed price of Kshs. 7 million. You are the judge at the Milimani Law Courts and the matter has been argued in your court. Decide the case, supporting your decision with the relevant principles and case law