Sure about vs Sure of

Do you wonder which one is correct?

The answer is that both are correct.

But they do not mean the same thing.

The difference is a tricky one, and you will make mistakes if you don’t understand it.

To learn more, read on.

 

Sure about (something)

Sure about can be extremely vague and can be used in a lot of different contexts.

“Sure about” means you are confident that you know something. It means you are confident that some information is correct and reliable. It means you believe that you have the knowledge of some details or facts that relate to a particular thing.

They don’t check passports or any ID when you arrive. I’m sure about that. (= I am confident that what I said is correct) Sarah is reliable and trustworthy. I am not sure about Adam. (= I do not know if he can be trusted) Never download an email attachment if you’re not sure about where it came from. (= if you do not know who sent it to you and what it is) I’ve broken up with her because I wasn’t sure about my feelings. (= I did not think I felt anything at all) Although now the sky is clear, you can never be sure about the weather. (= you never know if it is going to rain or not)

Sometimes a sentence could have several different meanings.

I am not sure about many things in life. (= I do not know what to do) (= I do not know what is right) (= I do not know why certain things happen) (= I do not know how to do something) My daughter is due next week, but I am not sure about the name. (= I do not know what name to give her) (= I have thought of a name, but I do not know if it is a nice name or if I like it) (= I have already decided what name to give her, but I do not know if it is a nice name or if I like it)

 

Sure of (something)

Sure of is used when you are certain that something is true, correct, exists, or that it is going to happen.

Unlike “sure about”, the “sure of” construction should only be used in very specific contexts, and only when talking about something very specific.

I am not sure of his name. (= I do not know what his name is) You have still got things to do. I am sure of that. (= I am certain it is true) I have seen this item before, but I am not sure of what it really is. (= I do not know what it is) We are sure of his support. (=We are confident that he will support us) It’s a fight they are not sure of winning. (=They do not think they can win) If we leave at 3:00pm we will arrive in good time and avoid entry queues. I’m sure of it. (= I am confident it will happen)

 

Similarities

Sometimes the difference in meaning is small. When that is the case, you can use the two phrases interchangeably.

Sam is not sure about what to do. Sam is not sure of what to do.

My daughter is due next week, but I am not sure about the name. My daughter is due next week, but I am not sure of the name.

You can never be sure about the weather. You can never be sure of the weather.

 

Differences

Sometimes the difference is stark and you should choose one over the other.

If we leave at 3:00pm we will arrive in good time and avoid entry queues. I’m sure about it.  If we leave at 3:00pm we will arrive in good time and avoid entry queues. I’m sure of it.

You’ve still got things to do. I’m sure about that.  You’ve still got things to do. I’m sure of that.

I am not sure about many things in life. I am not sure of many things in life.

We are sure about his support. We are sure of his support.

•  

Summary

• “Sure about” is a vague phrase that can be used in a variety of situations and contexts when you think something is correct,
• “Sure of” is used when talking about something specific that you think is true, correct, exists, or is going to happen.