A "humble heart" means having a modest and unpretentious attitude or manner. It means not bragging or showing off, but instead being kind, respectful, and open-minded. Full definition
She's the best and I say that with the most humble heart. (local.dmv.org)
Jesus wanted people with humble hearts who weren't afraid to turn from their sin and love of the world to follow him, to listen to his commands and become more like him daily. (nakedpastor.com)
Dust: An Elysian Tail is a 2D, Action, Platformer, Role - Playing Game by Humble Hearts LLC. (shortpause.com)