come hell or high water

Come hell or high water {informal}
(no matter what; that regardless of what happens, one is going to do something) — несмотря ни на что; что бы ни случилось; чего бы это ни стоило; ~ любой ценой
››› If you say that you will do something come hell or high water, you mean that you are determined to do it, despite any difficulties that there might be.

Example 1: I'll get you to the airport by noon, come hell or high water!
Example 2: I am going to be in Ivi City tomorrow come hell or high water!

Example 3: New York University's Adam Przeworski has found that democracies are “certain to survive, come hell or high water,” only if their per capita incomes exceed $4,000 a year: "A democracy can be expected to last an average of about 8,5 years in a country with per-capita income under $1,000 per annum… and 100 years between $4,000 and $6,000… Above $6000, democracies are… certain to survive, come hell or high water."

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Related vocabulary:
(come) rain or shine — что бы ни случилось