What is the ruling of Sharia on a person buying a piece of land from his stepmother for a low price, exploiting his knowledge of the future increase in the land's value after water is connected to it, while concealing this fact from the seller and her siblings, which led to their anger and accusations of fraud against him?

The transaction mentioned can be interpreted in two ways:

First: If the inquirer told the seller that he was the buyer, and the seller was unaware of the land's value, then what the inquirer did is forbidden by Islamic law and considered a betrayal. In this case, the buyer has the option [to revoke the sale].

Second: If the seller appointed the inquirer as an agent to sell, and he then bought it for himself, this is not permissible because suspicion is present.

Therefore, the inquirer must return the land to its owner if possible, or reconcile with him, or return its value.