Are covalent bonds truly covalent or in reality do they contain other bonding like ionic?

they are a mix some are more covalent than others and some are more ionic. You will find that certain compounds share properties of both. Also when you consider the differences in electronegativity ( the ability of an atom to hold on to its electrons) the one with the higher electronegativity will pull the electrons slightly closer towards itself. in compounds where the atoms have mively different electronegativity eg NaF the bond is clearly ionic and there is a clear difference in charge. in atoms where electronegativity is similar eg CH4 there is little difference in the charge and thus it is covalent.