Overpromise

We don't want to overpromise.

Source: wiktionary

So rather than posh skin creams that overpromise, a good brow job gives instant results.

Source: wiktionary

Hope Hicks, one of the President’s longest-serving aides, warned Parscale against touting ticket request numbers, reminding him that the number one rule in politics is not to overpromise and underdeliver, a source familiar with the matter said.

Source: wiktionary

"[...] If the economy has tanked... then we don't want to over-promise and under-deliver."

Source: wiktionary