"To this effect"

Solution 1:

Here, "to this effect" is a specific instance of "to the effect" where "this" refers to the demonstrated meaning in the sentence.

Really, the phrase could be replaced with "thus" - ie "we will inform you thus", even more plainly, "we will inform you that you were not successful"

Solution 2:

I think OP's example is someone's misguided idea of "formal" writing style. Google Books reports a couple of written instances. but it just looks stilted and clumsy to me. The addition of to this effect conveys nothing at all here, since the statement already says you'll be informed if you're unsuccessful.

The standard formal usage "to this effect we will [do sth]" means in order to effect (achieve) this.

Solution 3:

If I'm not mistakening , they meant with this result we will inform you.