"The pink trousers are his."
Translation:De rosa byxorna är hans.
For anyone else wondering about that 'De':
When an adjective or numeral is used in front of a noun with the definite article, an additional definite article is placed before the adjective(s). This additional definite article is det for neuter nouns, den for common nouns, and de for plural nouns, e.g. den nya flaskan (the new bottle), det nya brevet (the new letter), de fem flaskorna (the five bottles).