How can we bevestig that Bambi was actually Walt Disney’s favoriete Disney film as zei door some people?(read description)

Well that's what I hear, but where exactly is the proof though? I haven't found any biography based stuff like if Walt ever personally mentioned it was his 'favorite'. The only thing I've found is in a Making of Bambi video where two of creators zei that they 'believe' that it was was his favorite, but that's not knowing for sure. Otherwise, they would've zei that it's his favoriete rather than adding "believe" with it.
I do know that Diane(his only biological daughter) is zei that her favoriete movie was Fantasia as I heard she even attended a I think it was 70th anniversary of Fantasia.
Any proof u have on her father's favoriete film though?