What is the ruling on purchasing a property from someone who owns it with an official title deed, knowing that part of it was acquired from heirs in a state of joint ownership (undivided shares), and some of them accuse him of deception due to the low price and their unawareness of its true value?

It is permissible to purchase property from its owner, and selling undivided shares (mushaa') is permissible. The accusation of deceiving sellers and purchasing property at a very low price is not to be considered unless there is clear evidence, and the basic principle is the validity of contracts. If deception is proven, the contract remains valid, with the deceived party having the option (khiyar) if the overcharge/underprice (ghabn) is excessive. This does not affect the validity of the property purchase.