Reflection on the Holy Quran’s verses indicates that structure and meaning of some words and expressions of the Quran may cause receiving two meanings from one word in a single expression. This method in the Quran and commentary sciences is called “assurance”, tazmeen. The Islamic commentators have widely used this figure of speech in providing commentaries of divine verses to show literary-rhetoric features of the Quran. Ibn Ashour, the writer of “At-Tahrir va At-Tanvir” has considerably enjoyed this principle. In addition to dealing with semantics of “assurance”, its types such as literary, syntactic, rhetoric and prosodic ones are analyzed here. The Islamic commentators’ consideration from “assurance” is in accordance with definition of the grammarians from this phenomenon. Grammarians have divided “assurance” into three types including noun, verb and letter. The paper dealt with only that of verbs. Different Shiite and Sunni’s commentaries were used in analyzing the verses but emphasis is on the Ibn Ashour’s ideas and viewpoints.