In any financial investment, risk and return go in parallel. Guaranteed return is known as risk-free return, and almost always refer to either Fixed Deposit rate or Malaysian Government Securities coupon rate. If you are buying government bond such as Greece, it is no longer risk free anyway! FD rate seldom goes beyond 4%; here's a summary of the current risk free rate of return (FD).
Sharpe ratio of an investment refers to how well the investment generates a return taking into consideration the risk. Risk is high when the investment nature has high volatility - tendency for its value to soar or to plunge excessively within a specific timeframe when benchmarked against the overall market activity.
