Démentir belong to the 3
rd group.																			Démentir is a common french verb.
																																													
																									Démentir is conjugated the same way that verbs that end in : 
-tir
																									Démentir is conjugated with 
auxiliary avoir.
																																									Démentir verb is
									direct transitive.
																																									French verb démentir can be conjugated in the reflexive form: 
Se démentir
																									Démentir verb is a direct transitive verb, so passive voice can be used.