What is the safest way to get 8% return on retirement investments please be specific.?

Here is a thought for you. Nothing is guaranteed. Check out the better quality bank stocks. For example BAC. This company has raised its dividend every year for 10 years anyway. Ten years ago it paid 0.60 a share. Today it pays 1.90. The current dividend rate is 4.3% and that is tax advantaged. There is more than half of your 8% return. Do you think that the stock might appreciate the other 3.7%? It's historic appreciation is about 10% annually.

Of course diversification is the name of the game here. Never put all your eggs in one basket or one industry, or even one country, for that matter.

If I wanted an 8% return, I would select stocks that pay a dividend of at least 3% or maybe 4% that have prospects of price appreciation and I would make sure that at least 1/3 of them were foreign companies.

Here are some examples

DT 4.7%
ABN 4.7%
XEL 4.7%

find good municipal bonds with high returns (this probably means lower ratings, but as long as they don't default, you are good)

other investments are really not "guaranteed" - stocks could go either way

I say munis because they aren't taxed, but it depends on your income bracket. If you have little tax, you could go with corporate bonds, which offer higher rates, but then some of your gains will be taxed away.

If you mean over the long term (10-15 years), I'd put it in a low load mutual fund indexed to one of the markets. But really, over the next 10-15 years, it is projected that the market will only gain ~4-5% per year.

PS - If this was simple, people wouldn't make money (and lose money) doing this professionally!

Fixed income fund, balanced fund, tax free munis, investments along those lines. Not sure about 8% but with the tax benefits of munis it will approach that as a gross return. You can also put your money into a fixed annuity. They often have bonuses for the first 1-3 years which are well above 8% and also have tax deferrment.

Stocks that pay high dividends with little or no change in stock Price. I own Evergreen Advantage Fund (EAD) and Blackrock High Income Fund (HIS). Both pay about 8.8% per month plus a 12% end of year dividend. There are others out there, you just have to find stocks that pay high dividends. These are known as closed-end funds and not mutual funds.