The phrase "empty promises" refers to statements or declarations that are made with no intention of being fulfilled, or which lack any real substance or credibility. Full definition
This success against the odds can tell us a great deal about how the seemingly empty promises of international law can in fact be incredibly influential. (blog.politics.ox.ac.uk)
I won't make empty promises about the length of time or the final cost of resolving your case. (scribnerbankruptcylaw.com)
Like I said earlier, let us hold the presidential candidates accountable to realistic promises not empty promises. (ghanapoliticsonline.com)