colon with quotations and subtitles
The colon before a quotation or a subtitle.
A colon may introduce a quotation after an independent clause: The note was blunt: “Leave the key.” Use a comma after said and asked: She said, “Leave the key.” In a title, a colon separates the title from the subtitle: Plain Words: A Guide.
Examples
Use His reply was one word: “No.”
Use She said, “No.”
Avoid She said: “No.”