одно as “one thing”

Question

I read the following excerpt:

Он был арестован, без права переписка. Это значило одно: расстрел.

No doubt that одно, in this context, means "just one thing".

Can одно also be used in an expression like "I'll tell you one thing", when the purpose is to draw the attention of our listener to a particular detail?

Does "я тебе скажу одно" exist?

Answer 1

Oh, it's hard to message about it, 'cause it's more about intonation.

Can одно also be used in an expression like "I'll tell you one thing", when the purpose is to draw the attention of our listener to a particular detail?

The short answer is yes, you can translate it like this.

But я тебе скажу одно is more like I'll tell you just one thing.

I'll tell you one thing is closer in meaning to я тебе скажу одну вещь

Answer 2

Он был арестован, без права переписка. Это значило одно: расстрел.

In this sence the 'одно' word should represent the 'единственный, последний' meaning.

'I'll tell you one thing'

here the 'one' would mean completely different 'this particular thing/ secret/ advice etc.'

I'll tell you one thing is closer in meaning to я тебе скажу одну вещь

Exactly. По-русски так и будет: "Скажу тебе одну вещь."

Answer 3

No, it doesn't exist. You'd want to distinguish between "one thing only"--"одно" and "one thing/some thing"--"кое-что / что-то".

In your case: "я тебе скажу кое-что" / "я тебе что-то скажу".

Verb and object may exchange places or not, depending on the emotional load and/or one's fancy); the variant(s) with "что-то" may be considered more colloquial.