who has the Yes ready in him

You don't like song lyrics, eh? Here's a poem, then:

For some people there's a day
when they have to come out with the great Yes,
or the great No. It's clear at once
who has the Yes ready in him; and saying it,

he goes on to find honor, strong in his conviction.
He who refuses never repents. Asked again,
he'd still say no. Yet that no--the right answer--
defeats him the whole of his life.

['Che Fece...Il Gran Rifiuto' by Constantine P. Cavafy; trans. by Edmund Keeley and Philip Sherrard, in C. P. Cavafy: Collected Poems]