Henri M. said:
In addtition to my previous post, I would also like to give food for thought:
Victoria is a born royal and destined to become Queen of Sweden
Masako, Mathilde, Mette-Marit, Letizia and Camilla lived all their life long in their native country, have always spoken the native language and know about their country's history, society and culture.
Mary comes from the other side of the planet and has become a Danish royal. She did not speak Danish, did not know anything from Danish society and had to adapt to her new country. However Australia is a monarchy and Mary was at least known with the concept of monarchy.
Máxima also comes from the other side of the planet and has become a Dutch royal. She did not speak Dutch, did not know anything from Dutch society and had to adapt to her new country. She has even never ever lived in a monarchy and the whole thing of Queens and Princesses and nobles and golden carriages was far from her bed in republican Argentina.
So the starting point differs for all the ladies concerned. Seen in an objective way it were Máxima and Mary who had to come from far, litterally and figurally. They are a great success in the Netherlands respectively Danmark, so we could place them at number one, ex aequo.
This is at least a backing-up which goes furtherer than 'ah... princess xxx has always such a gentle style'.