The Dutch speakers in Belgium were too busy with improving their own lot directly than trying to reunite up with the Netherlands. Any pro-Greater Netherlands movement in Belgium only came up in the very latest parts of the 19th century when the Dutch speakers starting gaining more influence and their region became less of a backwater, and even at that time fighting the French-speakers for more rights had more priority. Really, sentiment for reunification is more of an early 20th-century thing, sadly beyond the scope of this topic.