What is the difference between "Anseetu Ayah" (أُنسيت آية - a verse was made to be forgotten by me) and "Naseetuha" (نسيتها - I forgot it)?

The meaning of "nasitu" (I forgot) differs from "unsītu" (I was made to forget). The first, "nasitu," means the speaker himself forgot, and it can carry two meanings: deliberate abandonment, which is blameworthy, or ordinary, unintentional forgetfulness. As for "unsītu," it means that Allah Almighty made him forget. It is forbidden to say "I forgot such-and-such a verse," as stated in the noble hadith: "How evil it is for one of them to say: 'I forgot such-and-such a verse,' rather, he was made to forget," this is to avoid the blameworthy meaning of abandonment and negligence, whereas it is not disliked to say "unsītu" because it attributes thefulness to Allah Almighty.