I see. You believe that Nieto is lying because you can’t even imagine the object of your worship lying, can you?
Somebody’s lying. It’s either Nieto (who has no reason to lie about this subject), or Trump (who has every reason to lie about this subject). Furthermore, Trump’s track record for lying is a pretty impressive one. About three quarters of his fact-checked statements are out-and-out lies, so he’s not exactly trustworthy.