On June 2nd, 1946, Jesus said, "Maria is My pen. Nothing more. I am the Writer. The Thought is mine. I can do what I want with it, then. And I want My Thought, translated into a Word through an impulse of Love, to go and vivify those who are dying on this earth, where the forces of Evil are so active"
(N:45-50). I highly recommend reading
A Summa and Encyclopedia to Maria Valtorta’s Extraordinary Work, especially the chapters on the proofs in support of Maria Valorta's writings having a supernatural origin.
On January 28th, 1947, Jesus said, "[...] it is proper to specify that the inspired writer
‘has God as the author'. God, Who reveals or illuminates mysteries or truths, as He pleases, for these instruments of His,
‘spurring and moving them with supernatural virtues,
assisting them in writing in such fashion that they rightly conceive with their
intelligence and faithfully seek to write and, with suitable means and infallible truth, express all of the things, and only those things, which are commanded by Him, God.' It is God Who, with a threefold action,
illuminates the intellect so that it will know the truth without error, by either revelation—in the case of still unknown truths—or exact recollection, if they are truths already established, but still rather incomprehensible for human reason;
it moves so that what the inspired one comes to know supernaturally will be written faithfully;
it assists and directs so that the truths will be stated
in the form and number which God wills, with veracity and clarity, so that they will be known to others for the good of many, with the very words of God in the direct teachings or with the words of those inspired when they describe visions or repeat supernatural lessons.
The Work which is given to men through little John [Maria Valtorta's nickname]
is not a canonical book. But it remains an
inspired book which I am giving to help you understand certain passages in the canonical ones and especially to comprehend what My time as Master was like and know Me—I, the Word, in My words.
[...] I nor he [little John] say that the Work is a canonical book. In all truth, though, I tell you that it is an inspired book [...]"
(N:45-50)