"You are the perfect daughter."
Translation:Du er den perfekte datter.
After a definite article or possessive, the adjective takes it's "e-form", which doesn't happen after the indefinite article. For example:
Et smukt hus = A beautiful house
Det smukke hus = The beautiful house
Mit/Hans/Sørens smukke hus = My/His/Søren's beautiful house
Huset er smukt = The house is beautiful