John Shield said that, in a "post-truth" world, the BBC has to understand and respond to audience needs to retain credibility.
He said: "In a world of infinite online information, where the most spurious assertion can pass into the public consciousness in the time it takes to type 140 characters, it has never been more important to separate fact from opinion, prediction from certainty."
Shield said that, while trust in the BBC remained high, with members of the public five times more likely to visit its news website to check facts than anywhere else, presenting facts was no longer enough and the broadcaster had to "earn the right to be heard".
The challenge emerged from the US election trope that the media took Donald Trump’s campaign tactics literally, but not seriously, while his supporters took them seriously, but not literally.
Shield said: "This is a distinction that highlights our major challenge for 2017: not only to prove ourselves as a source of trusted information, but also as a trusted messenger."
The solution, said the comms chief, is a genuine two-way conversation between the broadcaster and its audience, which began with it setting up 'audience councils' in the run up to the EU referendum.
These councils gave the BBC feedback on how it should cover the referendum, as well as feeding back perceptions of the campaign from different communities.
Shield concluded: "We are working hard to forge a new, genuinely two-way relationship with our audiences across every part of the corporation, and we have further to go. But in the ‘post-truth’ era, all of us have to recognise that, however reliable our information, if we cannot respond to the challenge of listening to and understanding the public, they will not take us seriously. Literally."