in one's wildest dreams

Prepositional phrase

in one's wildest dreams

1. (idiomatic, normally in the negative) Much better than one could ever expect.
   • 1843, Calderón de la Barca, 'Life in Mexico

     At the same time, the Count de B—— very philanthropically hired an old discolored-looking horse, which was grazing peaceably outside the hut, and mounting the astonished quadruped, who had never, in his wildest dreams, calculated upon having so fine a chevalier on his back, galloped off in search of more solid food, while we set the Indian women to baking tortillas.