He should have said, ‘I did it intentionally’ - היה לו לומר מזיד הייתי
Summary:
We can assume that מזיד הייתי is (also) not believed but nevertheless it makes for a valid מיגו, since it is a more acceptable claim, or we can maintain that מזיד הייתי is believed.
That an emergency developed on the way - דאיתיליד ליה אונסא באורחא
Summary:
We need to come on to דברים שבלב אינם דברים, in order to validate a sale where it was either difficult or virtually impossible to carry out the stipulation (depending on the two versions).