The role of grammar in talk-in-interaction has recently become a focal point of conversation analytic research. Yet how different clause types, such as declaratives and interrogatives, contribute to action formation is still rather vague. We approach this issue by looking at three questioning actions that are designed with a declarative prefaced by a specific lexical item: want, dus, and oh. We will demonstrate that each action presupposes that the speaker has a high degree of certainty: want is used to account, dus to infer, and oh conveys a change-of-state, typically from not knowing (K−) to knowing (K+). Based on these findings, we will argue that declarative questions are used when a speaker claims a particular epistemic stance, and in turn that epistemic stance constrains the actions that a clause type can be used for.