This is the 637th most frequent Indonesian word.
nya
"Nya" is an Indonesian possessive pronoun meaning "his," "her," "its," or "their," and can also function as a definite article or refer to something previously mentioned.
Here, 'nya' is a possessive pronoun indicating ownership.
Buku ini miliknya.
This book is his/hers.
In this sentence, 'nya' acts as a pronoun referring to the object being read.
Saya membacanya tadi malam.
I read it last night.
Here, 'nya' is used as a possessive marker to denote that the happiness is associated with someone.