Heavens to Betsy is a way of exclamation, used to express shock or being surprised in a fancy, old-school way.
The expression is often associated with old people, who would likely use it to avoid swearing or blasphemy.
People sometimes use the term in an ironic way as well, to act fake-surprised when something ordinary happens.
The exact origin of heavens to Betsy is currently unknown.
There are conjunctions that suggest the name Betsy originally referred to Betsy Ross, the woman who made the first United States flag in 1777.
Although even linguists often refer to the expression’s origin as “completely unsolvable”, we know for a fact that it first appeared in print in 1857.
The expression was very popular during 19th and early 20th century America, usually appearing in conversations where blasphemy and dirty words would not have been acceptable.
After the secularization of modern society, heavens to Betsy decreased in popularity.
In the 21st century, the term is mostly featured in image macro memes that show old ladies, and are used as reaction memes.