If you do something underfalsepretenses, youlieabout who you are, what you are doing, or what youintendto do, inorderto get something:
He wasdeportedforenteringthecountryunderfalsepretenses.
If you're not going toofferme ajob, then you'vebroughtme here underfalsepretenses(= you havedeceivedme inorderto make me come here).
I'mafraidI'm here underfalsepretenses. I said I wasrepresentingaclient, but that's nottrue.
I got into thebuildingunderfalsepretenses, but I didn't have anychoice.
Theykepthimlockedup foryearsunderfalsepretenses.