What is the meaning of Assert?

To declare with assurance or plainly and strongly; to state positively.

To use or exercise and thereby prove the existence of.

To maintain or defend, as a cause or a claim, by words or measures; to vindicate a claim or title to.

To insist on the legitimacy of one's rights, opinion, etc; not to allow oneself to be dismissed; to ensure that one is taken into consideration; to make oneself respected; to be assertive. See assert oneself.

To declare that a condition or expression must be true at a certain point in the source code (in some cases causing the program to fail if it is not, as a safeguard).

To set a signal on a line using a voltage or electric current.

Synonym of assertion

assert (conditional statement that checks the validity of a value)

Source: wiktionary.org