without fail
/wɪˌðaʊt ˈfeɪl/idiom
always; every time, with no exceptions
без исключений, непременно, всегда
Русский аналог: «как штык; обязательно»
Часто о привычках и обещаниях, в конце фразы: He calls every Sunday without fail.
“I check the weather every morning without fail.”
“He calls his mother every Sunday without fail.”
“Please send me the report by Friday without fail.”