It's a fond only occured by a human and a Digimon friendship and trust for each other. They said "You don't make a trust, you earn one", "To make a friendship exist, make sure you've earned a trust".

  In the end, you'll find out you both had the best bond together and righteously will never forget the memories you've made with your partner and they'll know, the thing isn't about being powerful, it's the bond between two.

-Pawn-