彼が助けてくれなかったら彼女は失敗していただろう。

She would have failed but for his help.

彼(かれ)が助(たす)けてくれなかったら彼女(かのじょ)は失敗(しっぱい)していただろう。

Kare ga tasuketekurenakattara kanojo wa shippaishiteita darou.

彼 (かれ)

he; him; his; boyfriend

が (が)

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

助ける (たすける)

to help; to save; to rescue; to give relief to; to spare (life); to reinforce; to promote; to abet

彼女 (かのじょ)

she; her; her; girlfriend; sweetheart

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

失敗 (しっぱい)

failure; mistake; blunder

だ (だ)

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

Readings: ヒ、かれ、かの、か.の

Meanings: he, that, the

Readings: ジョ、たす.ける、たす.かる、す.ける、すけ

Meanings: help, rescue, assist

Readings: ジョ、ニョ、ニョウ、おんな、め

Meanings: woman, female

Readings: シツ、うしな.う、う.せる

Meanings: lose, error, fault, disadvantage, loss

Readings: ハイ、やぶ.れる

Meanings: failure, defeat, reversal