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You can't make an omelet without breaking eggs.
Literal
Egg [object-を] break-not-without, omelet [topic-は] make-cannot.
A direct rendering of the English proverb. The ~なくては construction ('unless / must') sets up a necessary precondition: 'unless you break eggs, you can't make an omelet.' ~なくては has a slightly more colloquial, 'you really have to' feel than the equivalent ~なければ. オムレツ is the katakana loanword from French via English.