This is the short and the long of it

Meaning

The substance; the plain truth.

Origin

From Shakespeare's The Merry Wives of Windsor, 1600:

MISTRESS QUICKLY: Marry, this is the short and the long of it; you have brought her into such a canaries as 'tis wonderful. The best courtier of them all, when the court lay at Windsor, could never have brought her to such a canary.

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