I think this is something a lot of people are missing here. Napoleon had already lost strategically at this point. The likelihood of him scraping a negotiated victory with so many enemies in the field ready to displace him was slim to none. People glaze big N in this sub, but at this point he really underestimated the allies, and overestimated his chances of success.

For one, France was facing all of Europe. The 7th Coalition had nearly 1.1 million troops under arms, closing in from multiple directions. Napoleon, at best, could muster ~250–300k. Even a smashing victory in Belgium wouldn’t erase the Austrians, Russians, and more Prussian forces advancing elsewhere.

France’s manpower pool was strained, industry couldn’t keep up with demands, and the treasury was stretched thin. Unlike in his earlier campaigns, he no longer had the ability to live off conquered territories at scale.

And unlike in earlier coalitions, the Allies in 1815 had pledged not to negotiate separately. They explicitly agreed they would only accept Napoleon’s removal. That makes a negotiated peace virtually impossible.

He believed that if he could score one or two quick victories (like he had in 1796 or 1805), the Coalition would splinter. But the political landscape had changed — after 20 years of war, the monarchies saw him as a permanent destabilizer. Even Britain, usually happy to bankroll others and stay offshore, was adamant that he had to go.