1. An information processing apparatus for evaluating relevances between persons, the apparatus comprising: a memory that stores inputted names of a first person and a third person in a text database; and a processor configured to: detect a plurality of relevances between said first person and two or more second persons, and between said two or more second persons and said third person, in said text database, wherein said third person represents a target person, who is to be introduced to said first person by one of said two or more second persons, wherein said first person and said third person are detected by their names, which are input to said computer, and said two or more second persons are detected as names in said text database, wherein said plurality of relevances comprises at least one directed relevance and at least one undirected relevance between said third person and said two or more second persons, wherein said at least one directed relevance comprises: one of a positive and a negative directed relevance corresponding to positive and negative feelings, respectively, as expressed in said text database; and a weight of said one of a positive and negative directed relevance is determined by at least one of a value based on a frequency of occurrence of said one of a positive and a negative feelings as expressed in said text database, and a value based on a period of time from said one of a positive and a negative feelings as expressed in said text database to a current time; and wherein said at least one undirected relevance comprises: one of a positive and a negative undirected relevance corresponding to one of a positive and a negative acting together, respectively, as expressed in said text database; and a weight of said one of a positive and negative undirected relevance is determined by at least one of a value based on a frequency of occurrence of said acting together as expressed in said text database, and a value based on a period of time from said acting together as expressed in said text database to a current time; evaluate each of said plurality of relevances between said first person and said two or more second persons, and between said two or more second persons and said third person, to determine a maximal sum of weights comprising relevances linking said first person to one of said two or more second persons, and linking said one of said two or more persons to said third person; and output said name of said second person corresponding to said one of said two or more second persons, as an introducer of said first person to said third person.