Translation:Lei ha insistito.
Here you can find the conjugation for "insistere"
"Passato remoto" is pretty difficult, it should be introduced little by little, but "she insisted" can be translated as well as "Ella insisté", even if we would rather say "Lei insisté"
I have already suggested some people today to report to Duo that "Ella" is missing in the dictionary for the lessons you are studying.
You could send a support to ask that verb forms difficult like "passato remoto" are not to be found in easier lessons.
On the other hand, it is correct that Duo accepts this as a correct translation, since it is. That's the problem of having an infinitely growing database following users' feedback, in the end you happen having advanced stuff even in easier lessons. A ridesign of the structure of the lessons should be made every two or three months, to move sentences that became too difficult in the appropriate section, or directly in a new one.
Thanks. I was sad because I lost a heart because I only chose 'Ha insisto' as a translation for 'She insisted' from the three possible Italian sentences. I was wrong because I did not also click on 'Ella insisté', which, of course, I had never seen before. It does look a lot like the French 'Elle a insisté', so I could certainly have taken a stab at guessing what it might mean but I couldn't believe that they would put in something so completely new and different in the multiple choice. Now that you have explained how it works, I understand better why it happens. Thanks again for all your help!
Hallo marziota i've translated " insistette" and it was considered wrong, but i know that in italian is possible and correct this translation. It isn't a problem because i'm happy learning with duo's app. However i have signed with green flag at the duo'staff. Thanks a lot for your advice and observations, hallo and see you soon