Ain't is a common, normal slang word in English. It does make perfect sense, but it sounds very uneducated.
I would suggest that "ain't" is a rather archaic slang word. It's something that a gangster in the 1930s would say.
In that particular sentence, this form: "You ain't sure about nuthin'" is more common.
Ain't also has a historical interest. The first ever "talking movie" (movie with sound) was The Jazz Singer starring Al Jolson. The film is indeed an ordinary silent film for 20 minutes, just like any other "normal" film of the day, and then—this was astounding to the audience of the day—Jolson says: "Wait a minute, wait a minute, you ain't heard nothin' yet."
So, "ain't" was the 8th word ever uttered in the movies!
In fact, my grandfather who was a very keen movie-goer, was at one of the first performances of this first "talkie," and indeed he literally dropped his cigarette and fell off his chair at the moment when Jolson "opened his mouth and words came out." It's a great family story.
Ensure and enforce are indeed similar in that they are both transitive (i.e. they take a direct object), but not all transitive verbs are equal. Enforce only takes a noun or noun phrase (such as the rules) as its direct object, while ensure is more versatile (from a grammatical standpoint): while it can take a noun or noun phrase, it can also take a content clause (also called complement clause or that-clause; such as that the rules are followed) as its object. This has been established by usage and convention, and it is rare to see enforce paired with that. In this case, convention dictates the grammatical constraints, and therefore it is grammatically incorrect to use a that-clause as the object of certain verbs (such as enforce). Ngrams shows relative usages:
As you mention, you could replace enforce with ensure:
People then create laws to ensure that these regulations are being followed.
Or, if you want to keep the strength of enforce, you would need to change the direct object from a content clause to a noun phrase:
People then create laws to enforce these regulations.
Best Answer
Both are acceptable. "Wrong" sounds more natural to me, but "wrongly" is the more formal. If you like you could split the difference and use "incorrectly".
See more at Grammarist.