至極当然のことだ。の英語

That's perfectly natural.

That's perfectly natural.

Naturally.

Of course.

the condition of things being very much as they should be

Obviously.

This is quite in the nature [order] of things.

a dead certainty

Indeed, I am pretty serious.

to come out in the end

There is no doubt.

expectation of matter (being as expected, be natural and proper)

Of course.

That goes without saying.

that must be expected

being justly natural

That is inevitable.

a matter of course

That's the logical result.

bound to happen

This guarantees me par.

It is a natural consequence

Such a result was to be expected.

It is as I thought

I thought so

I knew how it would be.

a thing that is to be expected

It is quite [entirely] possible.

quite certain

That is for sure.