change (one's) spots

Translations
измениться кардинально
Despite his promises, he couldn't change his spots and continued his old habits.
Несмотря на обещания, он не смог кардинально измениться и продолжал свои старые привычки.
Definitions
To fundamentally change one's character, nature, or behavior, especially when it is believed to be impossible or unlikely. The phrase often implies that a person cannot truly change who they are at their core.
Words
change

verb
изменить
one

pronoun
свой
is

functional word
есть
spots

noun
пятна