COMMENTARY on 12:51
A. Yusuf Ali:

Translation:
(The king) said (to the ladies): "What was your affair when you did seek to seduce Joseph from his (true) self?" 1710 The ladies said: "(Allah) preserve us! no evil know we against him!" Said the ´Aziz´s wife: "Now is the truth manifest (to all): it was I who sought to seduce him from his (true) self: He is indeed of those who are (ever) true (and virtuous). 1711
Commentary:

1710  Joseph's message was conveyed by the messenger to the king, who sent for the ladies concerned. Among them came the wife of 'Aziz. "What was this affair?" said the king: "tell me the whole truth." (R).

1711  The wife of the 'Aziz stood by, while the other ladies answered. Their answer was grudgingly acknowledging the truth of Joseph's innocence and high principles, but holding a discreet silence about their own part in egging on the 'Aziz's wife to sin, wrongdoing and revenge. When they had done, she began. She did not mince matters. She acknowledged her own guilt, freely and frankly. This was no time for her even to refer to other ladies-their jealousy, their gross mindedness, their encouragement of all that was frail or evil in herself.

 

Muhammad Asad:

Translation:
[Thereupon the King sent for those women; and when they came,] he asked: "What was it that you hoped to achieve when you sought to make Joseph yield himself unto you?" 49 The women answered: "God save us! We did not perceive the least evil [intention] on his part!" [And] the wife of Joseph's former master 50 exclaimed: "Now has the truth come to light! It was I who sought to make him yield himself unto me - whereas he, behold, was indeed speaking the truth!"
Commentary:
49  Evidently, the King wanted to find out whether they had previously been encouraged by Joseph, or whether he was truly innocent. The noun khatb denotes "something that one has in view" or "desires" or "seeks to obtain"; and so the expression ma khatbukunna (lit., "what was it that you [really] had in view") may be suitably rendered as above.
50  Lit., "the wife of the great one (al-‘aziz)".