@Derk
It seems there might be a mismatch between the language settings of your transcriber and the voice you've chosen from the voice library. Since the transcriber is set to English, it might be affecting the pronunciation of the Dutch voice. To ensure a perfect Dutch accent, you should set the transcriber's language to Dutch as well.
Would you like me to assist you in changing the transcriber's language setting to Dutch to match the voice from the voice library?