How is “many's the” used?

In Going Clear: Scientology & the Prison of Belief (2015), one line is: “Many times, many times.”

Which movie is “many's the” from?

The clip at the top of this page is from Going Clear: Scientology & the Prison of Belief (2015).

Idiom

used to show that sth happens often

formal · Heard in 944 movies

many's the…
used to show that sth happens often
Many's the time I heard her use those words.

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

Many times, many times.

Said in 8 films · #1