What Made You Trust a Mobile App Developer?

I'm at the stage where my app idea is ready, but choosing the right Mobile App Development company has become the biggest challenge. Every provider promises quality and fast delivery, so it's difficult to separate genuine expertise from good marketing. While researching different options, I came across Xs One Consultants. Has anyone here worked with them? I'd really appreciate honest feedback, real experiences, and any advice that could help me make the right choice.