This is the 5142nd most frequent Turkish word.
ifadesinin
"Of its/her/his statement" or "of its/her/his expression."
This sentence uses 'ifadesinin' as a possessive form, referring to the expression belonging to something specific mentioned previously.
Öğretmenin konuşmasında en çok kullanılan kelime 'ifadesinin' olduğunu fark ettim.
I noticed that the word 'expression' was the most used in the teacher's speech.
Here, 'ifadesinin' illustrates a possessive genitive usage to describe the expression associated with goodwill.
Ders kitabında, 'iyi niyet ifadesinin' doğru kullanımı hakkında bir bölüm vardı.
In the textbook, there was a section about the proper usage of the 'expression of goodwill'.
In this context, 'ifadesinin' refers possessively to the expression, specifically the expression of sorrow that is a theme in the painting.