Assertion (noun) عمل توثیق، حتمی موقف، اقرار واثق

a confident and forceful statement of fact or belief.
Example: “his assertion that his father had deserted the family”
Pernicious (adjective) نقصان دہ، مضر،

having a harmful effect, especially in a gradual or subtle way.
Example: “the pernicious influences of the mass media”