1. A computer-implemented method of a computer system for analyzing emotion based on a messenger conversation, the computer system executing steps comprising: storing survey information of a user respective to a specific counterpart with whom the user wishes to analyze emotion; opening a conversation history in a form of text between the user and the specific counterpart; reducing, by the computer system, pattern types in the conversation history in the form of text between the specific counterpart and the user; determining context of the conversation history in the form of text thereby reducing context types; recognizing a pattern in the conversation history in the form of text, wherein the pattern types are reduced, and wherein the context types are reduced, and determining, by the computer system, the emotions of the counterpart towards the user based on the pattern; wherein the step of reducing the pattern types in the conversation history between the specific counterpart and the user comprises: grouping, by the computer system, the conversation history by grammar-based functions and significance-based functions; and converting, by the computer system, elements within the conversation history to abstract words, wherein the elements are decided in accordance with characteristics and situations regardless of emotion, wherein the step of reducing pattern types removes pattern information non-related to emotion and reduces pattern types related to emotion.