Arjuna's statement here carries a rare kind of weight. He says: O Keshava, everything You are telling me, I accept as entirely true. This is shraddha — faith. Not blind belief, but a trust that comes after listening carefully, weighing the evidence, and recognizing the teacher's integrity.
He then adds: neither the gods nor the demons can know Your true form. This echoes what Krishna Himself said in 10.2. But now the words come from Arjuna's own mouth. What was heard has been internalized. What was received has become conviction.