By the time the war had reached this point, quite a few wise people had begun considering how to bring it to an end. Whether that meant defeating Zeon or negotiating peace with Zeon, General Revil had also considered ending this year-long war through negotiations—a war that had already cut the world's population in half.
In the original plot, before the Zabi family had fallen, Revil had been willing to negotiate with Deguzuru. Although the final outcome had not been pleasant, it at least showed Revil's own thoughts. Now that the Zabi family, the instigators of the war and rebels intolerable to countless Federal officials, had collapsed, there was far less resistance to General Revil agreeing to peace talks.
With the push from even more supporters than in the original plot, it could be said that even if Revil had refused negotiations, he would not have been able to avoid them. With the Zabi family fallen, Zeon's pro-war faction had effectively ceased to exist. Moreover, the agreement Char had secretly signed with the Federation was extremely beneficial to the Federation itself. One of its terms was that Char would allow the Federation to send personnel to New Zeon to assist with its reforms. Naturally, those personnel would also be tasked with monitoring New Zeon's development, and they would have to enter New Zeon under hidden identities and become important members of certain departments.
That point alone was enough to make the Federal High-level unable to refuse. On top of that, Char was willing to gradually reduce the size of the existing military and steadily improve New Zeon's citizens' views of the Federation, with the first stage being New Zeon's formal integration into the Federation under an autonomous model within three years.
Every one of those secret agreements demonstrated Char's sincere