This is the 511th most frequent Romanian word.
acesteia
The word "acesteia" in Romanian is the genitive/dative singular form of "acesta" (feminine), meaning "of this" or "to this (one)" (feminine).
The word "acesteia" is used in the genitive case, referring to a feminine possessor associated with "casa" (house).
Aceasta este casa acesteia, decorată cu grijă.
This is her house, carefully decorated.
The term "acesteia" signifies possession (her book) associated with a feminine subject, in the genitive case.
Am văzut cartea acesteia pe masă.
I saw her book on the table.
Here, "acesteia" is in the genitive case, referring to the experience possessed by a feminine subject.