The principle of reasonable notice is considered one of the pillars of proving the meeting of minds to ensure the accuracy of the mutual assent given to enter a legally binding contractual relationship, which is an important variant in contract formation. This could be portrayed in a sales contract where the purchaser is sufficiently aware of the physical state and the descriptive condition of the purchased goods where the seller is not mistaken or misrepresenting the quality of the goods sold (contract’s subject matter). In fact, the seller is legally obliged to inform the purchaser about the actual condition of the goods, including any defects, as this might affect the purchaser’s decision to enter the contractual relationship, which, in turn, might affect the accuracy of the assent given. The study demonstrated that the legislator recognized the importance of the reasonable notice principle due to its practical importance in ensuring the accuracy of the mutual assent to enter the contract. This recognition could be evident through the general provisions that ensure the certainty of the subject matter (i.e., the goods in a sales contract), the purchaser’s general right to end the contractual relationship where the seller refrains from providing the reasonable notice as the contract in this case can be voidable, and through imposing a general legal duty on the seller to provide reasonable notice to ensure the certainty of the subject matter (i.e., the goods). The study on protecting the principle of reasonable notice was divided into three main sections. Firstly, the effect of the vitiating factors: mistake and misrepresentation on protecting the principle of reasonable notice was identified. Additionally, the adequacy of the current legislations in ensuring the mutual assent and protecting the contracted parties in situations where the subject matter is uncertain was studied. Secondly, the possible ways the purchaser may end the contractual relationship on the basis of uncertainty and defect of the goods where the contract no longer meets his needs were explored. Subsequently, the final section was dedicated to fixing the principle of reasonable notice and to render it a general legal burden on the seller, aiming to ensure that the purchaser is totally certain about the quality and state of the purchased goods.