I am trying to understand de plus and des plus as found in these passages.
From chapter 7 of La porte étroite by André Gide:
Quand Alissa m’accordait quelques instants, c’était en effet pour une conversation des plus gauches, à laquelle elle se prêtait comme on fait au jeu d’un enfant.
From part 1 of La Princesse de Clèves by Madame de La Fayette (édition Lepetit, 1820):
Jamais cour n’a eu tant de belles personnes et d’hommes admirablement bien faits ; et il semblait que la nature eût pris plaisir à placer ce qu’elle donne de plus beau dans les plus grandes princesses et dans les plus grands princes.
QUESTION
I understand that the Gide phrase une conversation des plus gauches means a most awkward conversation. How does it come to mean that?
What is the literal meaning of ce qu’elle donne de plus beau in Madame de La Fayette?
How would you say in French:
It seemed nature had taken pleasure in placing in the grandest princesses and princes what it gave (or had to give) of the most beautiful.
How would you say in French:
It seemed nature had taken pleasure in placing in the grandest princesses and princes what it gave (or had to give) of the more beautiful.
Is there any syntactic or other interaction I should be aware of between the two usages (Gide and La Fayette's)?
BACKGROUND
About question 1
If I were left to myself I would have guessed that des was de + les and that there was something implicit after gauches, maybe choses. So the thing would have seemed to mean a conversation of the most awkward things
But one of my grammar books says that un monsieur des plus charmants is equivalent to un monsieur très charmant and in English a most charming gentleman. Here too, left to myself, I would have come up with something like a gentleman of the most charming qualities, by supplying qualities myself.
Should I simply accept that un or une + singular form of noun + des plus + plural form of adjective equals a most + adjective + singular noun? Or is there some deep explanation?
About questions 2, 3 and 4
Please never mind how donne should be rendered in English. That's not my question here.
My guess as to question 2 is that the phrase is about the superlative. It would make little rhetorical sense to talk of the more beautiful as if what was the most beautiful were then reserved for kitchen maids and stable hands. So I am wondering why not put a le in there somehow. Maybe expressions such as au plus and du moins are relevant.