There are multiple definitions - click on the translation that matches your context.

påstand (generelt)

substantiv

full

assertion

noun

Definitions of assertion

the action of saying something, or of referring to your legal rights in justifying your actions, confidently and forcefully

They face many obstacles to the assertion of their legal rights.

when someone says that something is true, especially when said with confidence or force

How could he be so confident about that assertion?