You mean that there exists at least one hash such that hashFunc(paragraph+hash) = hash? Yup, that probability converges to 1-exp(-1) = 63%. So it's no guarante

You mean that there exists at least one hash such that hashFunc(paragraph+hash) = hash? Yup, that probability converges to 1-exp(-1) = 63%. So it's no guarantee, but if you have some wiggle room in the paragraph (change the wording slightly etc) you can probably make it work.