above board

above board AND honest and aboveboard AND open and aboveboard (honest(ly), without concealment, without deceit or trickery) — честно, в открытую; без обмана; открыто и честно; ~ с открытым забралом

Example 1: I want everything to be above board. No secret deals, no discussions behind the scenes. — Хочу, чтобы все по-честному было: никаких тайных сделок, никаких закулисных обсуждений.

on the level
[behind the scenes]
'Board' here is the old word for 'table', as in 'sideboard' or bed and board (=комната и еда) The whole expression was originally a gambling termand alludes to the fact that card players who do not keep their hands on the table (board) may be suspected of of cheating when playing a game (changing their cards under the table.)