“The most beautiful car in he world”
Yes, it seems he did say it, though his sincerity may be questioned. In “E-Type Magazine” May, 2017, an article about it says that the Ferrari biography “Ferrari, Lui” on p. 164, quotes Il Commendatore as saying “When the Jaguar E-Type is launched, he tells me that he considers it the most beautiful motor car in the world” – a second source besides Norman Dewis.
He goes on to add that he would like to own a Rolls Royce but he cannot afford it – though he could easily afford to buy the whole company.
But there you are, a second, Italian, source saying that Ferrari did indeed say it. I’m convinced!