A colon can be used in a sentence to emphasize an idea. Look at this example;
There is only one thing we can’t really buy: time.
Notice how the words before the colon make a complete thought. The word after the colon is the word that we are emphasizing.
Here are some more examples:
I would not survive without my two best friends: Tammy and Jean.
We are approaching my favorite season: fall.
My mom had a favorite phrase: Love conquers all.
Use a colon after a complete thought to emphasize a word or phrase.
It’s your turn. Finish this sentence with a word or phrase: I am rereading my favorite book: Did you add a book title? Good! That is how you use a colon for emphasis.