scared the hell

[Bridget]

What is the meaning of "hell" in this sentence?

"She scared the hell out of me when she stood on the edge of the cliff."

[Rusty]

What is the meaning of "hell" in this sentence?

"She scared the hell out of me when she stood on the edge of the cliff."
The phrase "scare the something out of " is an intensifier. Something could be a variety of profanities, vulgarities or euphamisms: hell/heck/devil/dickens/ or odiferous bodily secretions. The idea is that this "bad stuff" is so firmly embedded in a person that it takes a very large scare to shake it loose.

[Bridget]

But if hell is seen to be firmly embedded in a person, surely the person wouldn't mind having the hell shaken out of them.

[Rusty]

But if hell is seen to be firmly embedded in a person, surely the person wouldn't mind having the hell shaken out of them.
A person who uses the expression is not thinking about its literal meaning or etymology. He/she is just saying how very scared he/she was.