Continue to believe in it!
While there is understandable skepticism surrounding the release date of Kingdom Hearts 3– for now, it is allegedly coming out in 2018, but give that Square Enix takes release dates as suggestions more than anything, no one is quite convinced that will happen- Square, for their part, are continuing to insist the game will be out this year.
In the publisher’s latest financial report, Square Enix confirmed that Kingdom Hearts 3 is still scheduled for release in 2018, which indicates that for now, it is something the company is accounting for. The last time Square was so heavily insisting a game would come by a certain date, Final Fantasy 15 came out in 2016, as promised… so maybe they plan on repeating the feat with this game.
If so, we might know by the end of E3 when exactly the game is supposed to be planned for. Kingdom Hearts 3 is currently announced only for PlayStation 4 and Xbox One.