A person cannot change his/her nature or character, especially if it is bad.
هیچ کس نمی تواند شخصیت و ماهیت خود را تغییر دهد، مخصوصا اگر بد باشد.
نتوان شستن از زنگی سیاهی
ز ناپاکزاده مدارید امید که زنگی به شستن نگردد سپید
He swears he has changed and won't hit his wife again, but we cannot believe him. A leopard can’t change its spots. We don’t want to risk his wife's life by sending her back to his house.
پلنگ نمی تواند لکه های بدنش را عوض کند.
(a) leopard cannot change its spots
a leopard cannot change its ˈspots idiom
(saying) people cannot change their character, especially if they have a bad character
• You didn't really expect her to be on time, did you? A leopard can't change its spots.
Main entry: leopard idiom