Confident about/in/of

I read the adjective confident collocates with about, in and of, and the example sentences below in Oxford Collocations Dictionary.

We are confident about the future.
I'm very confident in our ability to maintain leadership.
I'm fully confident of winning the title.

I want to know the nuance among confident about, in and of.
I read other example sentences in Oxford Advanced Learner's English-Korean Dictionary:

The teacher wants the children to feel confident about asking questions when they don’t understand.
We are confident in our expectation of a full recovery.
Buoyed by their win yesterday the team feel confident of further success.

I assume confident about means not scared of something that is coming or will happen; confident in is used when you talk about an ability, possibility or potential; and confident of is used when you talk about a result or outcome.

I'd like to know the difference more clearly. I guess it depends on the usage of the preposition. If you can explain the nature of each preposition together, I would really appreciate it. But I would be thankful for any explanation.

Question

Confident about/in/of

I read the adjective confident collocates with about, in and of, and the example sentences below in Oxford Collocations Dictionary.

We are confident about the future.
I'm very confident in our ability to maintain leadership.
I'm fully confident of winning the title.

I want to know the nuance among confident about, in and of.
I read other example sentences in Oxford Advanced Learner's English-Korean Dictionary:

The teacher wants the children to feel confident about asking questions when they don’t understand.
We are confident in our expectation of a full recovery. 
Buoyed by their win yesterday the team feel confident of further success.

I assume confident about means not scared of something that is coming or will happen; confident in is used when you talk about an ability, possibility or potential; and confident of is used when you talk about a result or outcome.

I'd like to know the difference more clearly. I guess it depends on the usage of the preposition. If you can explain the nature of each preposition together, I would really appreciate it. But I would be thankful for any explanation.

Answer

Trying to understand prepositions in English is only a little bit easier than trying to understand English spelling!

I think you summed it well in your second last paragraph. A better understanding will probably only come with looking at more examples.

Keep in mind these can sometimes substitute for each other. For example,
"I am very confident of our abilities" is good.

I am sorry I can't be more help, but you have a good understanding already.

Answer

Your deductions seem pretty good. I’d also add that ‘confident of’ is rarer and higher register.