corner on the truth

have a corner on the truth (think that only you have the truth) — быть истиной в последней инстации; претендовать на монополию на истину

Example 1: I can’t believe she actually said that! Does she really think that she has a corner on the truth?

Example 2: You folks have no corner on the truth — you have an opinion just like everyone else.

Example 3: I would characterize that as an effort to convince us that they knew best, they had the corner on the truth, and that our, our role was to sit quietly and consume the information that they wished to provide to us.

Frequency of usage: sometimes