without mistakes or faults in English:

impeccable apperance. reputation

This restaurant has built its reputation on impeccable service.

faultless; flawless; irreproachable. If you describe something such as someone's behaviour or appearance as impeccable, you are emphasizing that it is perfect and has no faults.

His English is impeccable.

His reputation was impeccable.

She's taught her children impeccable manners.

It requires both, high quality raw materials as well as impeccable burning characteristics.

Sara's figure skating performace was impeccable and she received highest possible notes.

I also made a point to maintain an impeccable appearance. I did not want to look the part of a sick person at this early stage.

in accordance with the highest standards of propriety; faultless; perfect. They were in absolutely impeccable form that night.

She speaks impeccable English.

impeccable manner

The service at the restaurant was impeccable.

the dining options are impeccable

He has impeccable manners, which means you can never be sure what he actually thinks!