Adding bem (lit. ‘well’) to a modalized proposition, as in it is quite possible that he already left, increases the degree of conviction being conveyed. Apparently, this epistemic reinforcement that results from the presence of bem corresponds to the expression of a higher degree of belief than what is expressed without bem. Concretely, while é possível que p (‘it is possible that p’) indicates that p is a possibility, é bem possível que p (‘it is quite possible that p’) will indicate that p is a good possibility. If so, the meaning of constructions resulting from the addition of bem to a modalized proposition can be captured within the framework of modality analysis in Krazter (1991, a.o.), who considers different degrees of modality, including the notions of possibility and good possibility. This way, it will be understandable why bem can co-occur with weak modals, as the equivalents of possible or may, but not with strong modals, such as the equivalents of must or have to, since the latter already have a strong value, not being able to be reinforced by the addition of bem. However, there are counter-arguments to this hypothesis, which, among other problems, does not explain why bem may co-occur with various types of modal operators or propositional attitude verbs that express a strong epistemic value, such as, e.g., certo (‘right’), as in é bem certo! (‘quite right!’), or to know, as in the equivalent of he knows well that he is late. Thus, two questions arise: (i) how to explain the epistemic reinforcement resulting from the addition of bem to a sentence with an epistemic modal operator? (ii) why can bem combine with some epistemic modal operators, but not with all of them?An alternative hypothesis is presented and explored, according to which bem does not contribute to the truth conditions of the sentence, but functions at the discursive level. Specifically, the proposed hypothesis is that the addition of bem to a modalized proposition indicates the expectation that this proposition will remain valid as discourse flows. That is, bemhas the function of making the proposition in which it occurs persistent. Thus, the meaning of the constructions resulting from the addition of bem to a modalized sentence is best captured by an analysis of modality within dynamic semantics. In dynamic semantics, the meaning of a sentence is its Context Change Potential, its capability to update the information of the context (or information state) relative to which it is asserted. The proposed analysis provides an answer the two aforementioned questions. Epistemic reinforcement conveyed by bem corresponds to expressing the expectation that the modalized proposition will remain valid as discourse flows. The reason why bem can co-occur with some, but not all, epistemic operators is linked to the type of epistemic state described by each sentence. As predicted by the proposed hypothesis, bem cannot co-occur with modal operators expressing an inference that arises from particular information and that may not be maintained as new information is gathered.