The best known type of divergence is the bullish divergence. It is essentially a bullish warning that occurs when the price-action shows a lower low, but a momentum oscillator denies that by exhibiting a higher low.
Effectively, one has been warned in that instance that the asset may start to rise to align with the momentum oscillation. It is a discrepancy or latency that needed to be confirmed by a direct trading signal given by the price-action.
Therefore, if there is no confirmation, one can not yet place a bullish trade because it just a warning. Though, one should never disregard a bullish divergence warning, it is a mistake to take it as a direct trade signal.