noun
written expert opinion; certificate of authenticity; written appraisal
A formal document issued by an expert or appraiser, often used for art, antiques, real estate, or legal matters.
この絵画には鑑定書が付いている。
This painting comes with a certificate of authenticity.
不動産の鑑定書を取得する。
Obtain a written appraisal for the real estate.
証明書 is a general certificate proving a fact, whereas 鑑定書 specifically involves expert evaluation and opinion.
Compound of 鑑定 (expert appraisal) + 書 (document). The reading is standard on'yomi.