たとえ何が起ころうと、冷静でなければならない。

Whatever happens, you must keep calm.

たとえ何(なに)が起(お)ころうと、冷静(れいせい)でなければならない。

Tatoe nani ga okorou to, reisei denakerebanaranai.

仮令 (たとえ、たとい)

even if; no matter (what); if; though; although; supposing; supposing that; -ever

何 (なに、なん)

what; how many; you-know-what; that; whatsit; what's the expression; what do you call them; what?; hey!

が (が)

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

起こる (おこる)

to occur; to happen

と (と)

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

冷静 (れいせい)

calm; composure; coolness; serenity

だ (だ)

be; is; indicates past or completed action; indicates light imperative

Readings: カ、なに、なん、なに-、なん-

Meaning: what

Readings: キ、お.きる、お.こる、お.こす、おこ.す、た.つ

Meanings: rouse, wake up, get up

Readings: レイ、つめ.たい、ひ.える、ひ.や、ひ.ややか、ひ.やす、ひ.やかす、さ.める、さ.ます

Meanings: cool, cold (beer, person), chill

Readings: セイ、ジョウ、しず-、しず.か、しず.まる、しず.める

Meaning: quiet