‘There’s no benefit….’ and ‘It’s no good doing….’

[Helmey]

Hello everyone. .

I have a question about these phrases ‘There’s no benefit….’ and ‘It’s no good doing….’

Which of the following sentences is correct?

There is no benefit in expecting something good from such a man.
There is no benefit to expecting something good from such a man.
There is no benefit to expect something good from such a man.

I checked this phrase ‘There’s no benefit….’ in the Internet and I found three forms of that phrase:
There is no benefit in doing……….
There is no benefit to doing……….
There is no benefit to do ……..

I’m really getting confused !!!I don’t know which one is the correct answer and what does each form of them mean? Is there any difference between these two phrases ‘There’s no benefit….’ and ‘It’s no good doing…….’?

I was trying to understand them by myself but I couldn't, so I asked some friends of mine who knows English much better than me(friends from Zambia and Nigeria) but they couldn't explain that and they were confused too.

Could anyone please explain that to me?

Thanks in advance.

[Mister Micawber]

.
No difference in meaning. The first 2 are OK, but the last is a wrong structure.

Ms Google gives:

1,030 for "There is no benefit in doing"
1,960 for "There is no benefit to doing"
29 for "There is no benefit to do"

Such low-count retrievals as the 3rd one here should not be considered acceptable grammar.
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Native English teacher at Mister Micawber's

[Helmey]

I'm really happy that you replayed my post and what you explained is really helpful for me.
Thank you very much Mister Micawber.