Quote Originally Posted by storm View Post
Technically you're not supposed to begin a sentence with "But", which is perhaps why they chose to punctuate it the way they did. However, it would not have been wrong to just connect those two sentences with a comma on both sides of "but worry not".
This caught my attention after another thread linked to this one. The technical aspect you mentioned is actually incorrect. Many people have been told, in school, that certain words shouldn't begin or end sentences, but that isn't really true. Any word can begin or end a sentence, the sentence itself just has to make sense within the context of the language. But, (see what I did there, lol) in formal writing, certain words are considered "wrong" only because they are considered informal, when a more formal word would be more appropriate. Think of it like using "but" verses "however", "but" is informal and "however" is more formal. Really it comes down to who your audience is that determines how you speak and what words you use.