As safe as a house means "safety"; There is no risk of failure, which means "very safe". This idiom is equivalent to the idiom "as safe as the Bank of England". Both idioms mean very safe without any risk. ?

1850, in the sitcom timur Tatar, there is such a doggerel:

Come on, sacrifice your son and do the right thing.

No.-I don't think I see it that way.

Well, then, I promise you.

Will be as safe as a house. As a wife

Timour's sword made the widow lonely and sad,

I think my proposal is not bad at all.

Some people think that this idiom comes from this.

Some people think that this idiom originated in19th century, when many people bought risky stocks. Due to the economic bubble, many people went bankrupt, but it was relatively safe to invest in housing. So this idiom means very safe.

No matter where this idiom comes from, it means "very safe".

Example:

I locked your jewels in the drawer, so? As safe as a house.

I locked your jewels in the drawer, so it's safe.

If you fix the brakes, will the car get better? As safe as a house.

Fix the brakes and the car will be very safe.