How can we confirmar that Bambi was actually Walt Disney’s favorito! disney film as dicho por 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 dicho that they 'believe' that it was was his favorite, but that's not knowing for sure. Otherwise, they would've dicho that it's his favorito! rather than adding "believe" with it.
I do know that Diane(his only biological daughter) is dicho that her favorito! movie was Fantasia as I heard she even attended a I think it was 70th anniversary of Fantasia.
Any proof tu have on her father's favorito! film though?