The role of realtor is very important in a real estate transaction. Signing the real estate contract of sale is not an easy task the general public without the assistance of the experts into great detail to investigate and verify because of complex rights relationships, as well as process limitations in the real estate. Therefore, it is common to conclude the real estate contract of sale using the knowledge and experience of the specialist realtors who are expert in real estate transactions. Law for licensed real estate agent impose the verification of brokerage objects and the duty to explain on realtors when they deal in real estate for the benefit of the general public. Even though law for licensed real estate agent impose that relators must verify and explain about important matters on a deal when they were asked to mediation real estate sales for client and sign the contract of sale, if realtor violates the check real estate brokerage object and the duty of explain, the effect of private law is a problem related to characteristic of law for licensed real estate agent, that mean is whether their behavior is breach of duty on the deal or tort. In this paper, we classify the generated conflict which realtor is involved in conclusion of a contract and consider that the problem. We examine whether realtors are able to cancel the contract of real estate sale directly with the violation of the duty to explain and the verification of brokerage object or not, in this case, we also consider the relationship between contractual obligations and check brokerage object and the duty of explain. Moreover, if brokerage contractual relationship are existed between realtors and clients, realtors will be charged the fiduciary duty. therefore we also consider the relationship between fiduciary duty and the verification of brokerage object and the duty of explain. Furthermore, if realtors breach the verification of brokerage object and the duty of explain in case brokerage contractual relationship are existed between brokers and clients case, we can demand damages for default. However, in this case, law doesn't be taken constitution of law by default liability and law is taken the constitution of law by tort liability. we also consider what makes different conclusion depending on the constitution of law.