Turn out and prove

[ROBINDESBOIS]

I dont´aunderstand why sometimes we use one and not the other. In certain contexts I do understand, but in the sentences below I don't.

The stranger turned out to be her cousin why not proved?
It turned out that he had just arrived from Australia
His guess proved correct why not turned out?

That proves that he had nothing to do with the murder.


Can I use both in all of them or just the ones that I suggested?

[Rusty]

I don't understand why sometimes we use one and not the other. In certain contexts I do understand, but in the sentences below I don't.

The stranger turned out to be her cousin. Why not proved?
It turned out that he had just arrived from Australia.
His guess proved to be correct. Why not turned out?

That proves (that) he had nothing to do with the murder.

Can I use both in all of them or just the ones that I suggested?'Turn out to be (something/one)' and 'Prove (to be) (something)' are not synonyms.
The first means that something/one eventually becomes something or is discovered to have a particular quality.
The second means that something/one shows or provides evidence of having a particular quality/trait.

His guess proved (to be) correct. (There was evidence that his guess was correct.)
His guess turned out to be correct. (The proof he was right came later; his guess became correct. Sometimes the speaker expresses surprise.)

The stranger proved to be her cousin. (This is a statement of fact. There is evidence that backs this claim.)
The stranger turned out to be her cousin. (The truth was discovered later.)

It proved to be that he had just arrived from Australia. (Later analysis indicates this was the case.)

It turned out that he had nothing to do with the murder. (Investigation resulted in no evidence, so the person was no longer under suspicion. When you use 'proves' in a sentence, you're saying evidence exists.)

[ROBINDESBOIS]

They are not synonyms but they are very confusing.

[poli]

It is confusing because language is a very fluid. The two terms do not have the exact meaning, but their meaning is similar. Turned out, has a lower register. After all, proof is scientific or mathematical.