Why did people think Prussia and Germany would try to prevent a war?

I don't think any European powers thought they would be peaceful. Germany formed out of a continuous victorious Prussian Army under the Hohenzollern dynasty turning them into a virtual military superpower the world had never seen, after so many wars the Kingdom, then State of Prussia was dissolved permanently in 1947, half of Prussia was handed to Poland. Prussia (PREUSSEN) has never been a peaceful kingdom, or state