This is the 10359th most frequent Turkish word.
binasını
"His/her/its building" or "the building of him/her/it" (possessive form).
In this sentence, "binasını" represents the possessed building, indicating ownership with the possessive suffix "-ı" and the accusative case due to the specific action directed toward it.
Ali yeni binasını boyamak istiyor.
Ali wants to paint his new building.
Here, "binasını" refers to the building of the school, with possessive suffix "-ı" denoting relation and again in the accusative case for the action of renovation.
Okul binasını yenilediler.
They renovated the school building.
"Binasını" indicates the building owned by the director with the possessive suffix and is in the accusative case due to the transitive verb "hazırladı" requiring a direct object.