The president made the promise to Chibok parents while addressing the recently-released Dapchi girls.
112 girls are still in Boko Haram's custody after militants invaded Government Girls Secondary School in Chibok and kidnapped 276 female students in April 2014.
The president made the promise of their return while speaking during a reception of the recently-released Dapchi schoolgirls who were returned by Boko Haram after they were abducted in February 2018.
During his address on Friday, March 23, 2018, the president said the return of the Dapchi girls is a fulfillment of his promise to their parents, and used the occasion to appeal to Chibok parents to retain hope.
He said, "While parents of the Dapchi girls rejoice because of the reunion with their children, I want to appeal to the Chibok Community never to lose hope or to despair.
"We are determined as never before, to bring back our remaining Chibok daughters. And this, we must accomplish. And that will be soon, by God's grace."
Even though the Chibok girls were abducted during the administration of then-president, Goodluck Jonathan, the president secured the release of 103 of them after he was inaugurated.
In a report that was published by the Wall Street Journal in December 2017, President Buhari approved the payment of €3 million to Boko Haram to facilitate the release of the girls.
He approved the sum of €1 million for the release of 21 schoolgirls in October 2016, before approving another €2 million for the release of a further 82 girls in May 2017.
Five Boko Haram commanders were also released by the Army as part of the deal.