Negotiation had repeatedly been made withe nazi government. They repeatedly abrogated the treaties and agreements whenever convenient. By 1939 few heads of state believed anything the German government promised. That continued into 1940, 41, 42.
China had a history of negotiations with Japan, and agreements. Japanese policy was to demand more, and in 1937 they abrogated the earlier treaties and started a new war with China. Chinese attempts to negotiate failed, and US efforts to negotiate in 1941 failed miserably as well. Japan instead expanded its wars invading four other nations as well. When Japan attempted to open peace talks in 1945 their proposals were as if they had won the Pacific war, not on the verge of losing it. They also at the same time attempted to create a alliance with the USSR.
In both cases there was a solid history of duplicity and failure in negotiating with both Japan and Germany.