I'm not sure how this sentence means what it means. Isn't it like "nothing is far from the truth", no?

Native speaker’s answer
Rebecca
Not quite! If something "couldn't be further from the truth" it is so far from the truth that it is false. It is completely untrue. Ex: I was once told people can't change. But nothing could be further from the truth. People change every day. Ex: Nothing could be further from the truth. Of course, I don't want to leave.