1. A method for guiding a conversation based on cognitive analytics, the method comprising: receiving, from a conversation interface, while the conversation is continuing, data of the conversation up to a time in the conversation; receiving while the conversation is continuing, current data from a data source, the current data relating to a remote participant in the conversation and a topic in the conversation; computing, as a part of the cognitive analytics, using a processor and a memory, from the current data and the conversation data, a measurement of a sentiment value of the remote participant during the conversation; introducing, while the conversation is continuing, data of a prompt into the conversation, wherein the data of the prompt is configured to cause the conversation to increase the sentiment value of the remote participant; and updating a profile of the remote participant with the sentiment value, to form an updated profile; and using the updated profile as a second data source in a later portion of the conversation.