The function of colon is to attract the reader's attention, which leads to the following contents. Its pause is more meaningful than comma or even semicolon, but weaker than period. Colons can mean coercion and command, or they can mean endless meanings. English is more accustomed to using commas to lead to direct speech.
Yes, Miss Manette is getting married. ? Use commas to introduce direct speech. He added, "Yes, ...".
Extended data:
You can't abuse the colon.
1. colon cannot be used between a verb and its object or object complement. For example:
Some important vitamins in vegetables are: vitamin A, thiamine, niacin and vitamin C. (The colon should be removed)
2. You can't use colons between prepositions and their conjunctions. For example:
The area to be painted includes three gable ends, six ten-story windows and a front porch. The colon should be removed.
3. You cannot use colons after such as, contains or examples.