Finding reliable developers will always just be a risk you take. I would say Talent Hub would be your best choice but yet again you never really know if they are going to end up scamming and not doing what you assigned them to do. I mainly use Twitter to find reliable developers and that might be your best choice but it is hard to find some on Twitter. No matter what your going to be taking a risk and gamble on finding reliable devs but my suggestion to you is probably Twitter cause i have gotten reliable developers from there that do great work