How can I say a project can return its investment?
Is my following sentence correct?
Although this approach is costly to establish due to a need to gather a huge amount of data, it is reliable and a smart solution and can return the investment.
The usual phrase used for this sort of thing is Return on investment, or ROI.
While your example is OK, you could use the above with some rewriting:
Although this approach is costly to establish due to a need to gather a huge amount of data, it is a reliable and smart solution, and can provide a substantial return on investment.
(I also edited your articles a bit.)
If you simply want to state that the project is capable of recovering the amount of money invested in it, you can say that it can break even. It is normal to estimate how long it will be before this happens:
the project can break even within x years
If you want to go on to say that the project will make a profit, you can add
and the project will offer/provide a return on investment of x% over y years.
If you want to talk about return on investment, rather than simply break even, then investors will expect a much more detailed financial plan: best avoided unless you have a detailed knowledge of the financial aspects of project management.
This is more correct, commas go in pairs:
Although this approach is costly to establish, due to a need to gather a huge amount of data, it is reliable and a smart solution and can return the investment.
In terms of the wording, it was fine.
Also, "it's" is always, always, always a contraction for "it is" - pronounce "it's" to yourself as "it is" when reading or writing it, and you will never again get this wrong. So, to be clear, "return it's investment" isn't right at all, but only because you should have used the possessive "its" instead of "it's," which is a contraction for "it is."