If one is interested in going into business/dating an individual, or really any interaction where complete knowledge of the other party is necessary, it is permitted to ask people what they know about the individual. Since it is being done for a constructive purpose and not for the sake of sharing gossip, it is permitted.
However, one should make sure to inform the one asked as to why you need this information. (You need not tell them the exact details but they must know that this is for a constructive purpose and it is not gossip.) This is because if the one who is sharing the information does not realize that it is permitted they are violating the prohibition of lashon hara by sharing this information, since from their limited perspective there is no positive purpose in sharing this information.