This is the 18th most frequent Norwegian word.
sin
"Sin" in Norwegian is a possessive pronoun meaning "his," "her," "its," or "their," referring back to the subject of the sentence.
The word 'sin' here expresses possession by the subject 'Han' (He).
Han tok sin bok fra bordet.
He took his book from the table.
'Sin' indicates possession related to the subject 'Hun' (She) in reference to the 'prestasjon' (achievement).
Hun er stolt over sin prestasjon.
She is proud of her achievement.
'Sin' refers back to the subject 'De' (They), showing collective ownership or personal possession aligning with the subject.