Is 'the least I know, he is an outsider' valid?

Is this a valid sentence:

The least I know, he is an outsider.

I'm just trying to say that even though I know lots of other information about him (which may or may not be entirely correct), one thing which I can tell for certain - he is an outsider.

So does my statement above clearly support that? Is it valid or is there a better way to say it?

Solution 1:

The phrasing in the sentence in the question is a little awkward.

You could keeping the construction as it is, but add some words to make it less awkward:

The least I know about him is that he is an outsider.

However, that doesn't necessarily say anything about knowing truthful things about him. So, you could add that too:

The least I know about him that is truthful is that he is an outsider.

But while that now expresses everything, it's somewhat long-winded.

The original shorter version can be used if the words are rearranged (and the actually removed):

✔ I know he is at least an outsider.

I think that's the shortest version that conveys everything. Even the fact that it's truthful is conveyed (without having to state it explicitly) because this version of the sentence doesn't talk about the least that you know, but the least of the attributes or properties that are his.

Using different phrasing, there are some other possibilities:

At the least, I know he is an outsider.
If nothing else, I know he is an outsider.