Not entirely correct.
The Dutch anthem starts:
"William of Nassau am I, of German descent;
True to the fatherland I remain until death.
Prince of Orange am I, free and fearless.
To the King of Spain I have always given honour."
It's saying that William I, Prince of Orange has German descent, and that's correct, he was born in (what is modern day) Germany but he is seen as the father of the Dutch nation.
That said, for a long time the Dutch didn't really see themselves as completely distinct from Germans.
They called their language "Nederduits" (Nether-German) or "Diets" which is the Dutch cognate of the German word "Deutsch".
Same on the German side. As late as the 1800s the Bavarian King Ludwig I added Dutchmen to his Walhalla Museum because he considered Dutch to be a dialect of German.
Dutch anthem is even worse:
- No intro
- It starts with saying the Dutch have German blood
- It end with saying that the Dutch have always praised the Spanish King (NL was a Spanish colony and rebelled against additional Spanish taxes)