Frankly, an awful lot of the supposed 'AA Milne' or 'Winnie the Pooh' quotes seem stylistically very unlikely and I suspect them of being from the Disney films rather than anything Milne wrote.
For example ""If you live to be a hundred, I want to live to be a hundred minus one day so I never have to live without you." does not appear in 'Winnie the Pooh' as stated. In 'The House at Pooh Corner', Ch X 'An Enchanted Place', Christopher Robin says "Pooh, promise me you won't forget about me, ever. Not even when I'm a hundred" but that's the only reference to living to be a hundred in either book.
"If ever there is tomorrow when we're not together... there is something you must always remember. You are braver than you believe, stronger than you seem, and smarter than you think. But the most important thing is, even if we're apart... I'll always be with you" and
"Promise me you'll always remember: You're braver than you believe, and stronger than you seem, and smarter than you think" are not in either book and no reference is given at all other than 'AA Milne'.
It would be impossible to prove he never said or wrote those words, but the use of 'smarter' to mean 'more intelligent' would indicate that they came from an American rather than an Englishman, to whom it means 'better-dressed' or possibly 'cheekier'.
