Redoubled certainty, or certainty in the strict sense, is a firm and true belief in a proposition so that the possibility of its negation is deemed impossible. It is sometimes assumed that this certainty cannot apply to personal propositions, which this study addresses. Four conditions are set for redoubled certainty: 1. firm belief in the content of the proposition. 2. belief in the impossibility of the proposition’s negation. 3. correspondence with reality and truth. 4. the permanence of this belief. The fourth condition of redoubled certainty is that this certainty must never change. According to this condition, some believe that redoubled certainty does not apply to personal propositions because certainty in these propositions changes with the person’s state. The subject of this study is the application of redoubled certainty in personal propositions; therefore, the flow of argument in these propositions or the argumentativeness of mystical propositions, which are personal, is outside the scope of this discussion. However, these matters are among the effects of the flow of redoubled certainty in personal propositions. To address this issue, three answers can be provided: 1. the invalidity of the permanence condition in certainty, 2. considering the precise time condition in certainty, and 3. confusion between certainty and the object of certainty. It can be said that these responses share a common spirit: in redoubled certainty, correspondence with reality is necessary. To achieve correspondence with reality in personal propositions, the time condition must be considered, and with this condition, permanence is also achieved. The method of this study is library-based.