C2
If these discussions are to succeed, we'll need openness from/on both sides.
- aboveboard
- anti-corruption
- artless
- artlessly
- artlessness
- earnest
- honestly
- in
- in all honesty/seriousness/truthfulness idiom
- in good faith idiom
- integrity
- joking apart/aside idiom
- sincerely
- stainless
- straight arrow idiom
- straight up idiom
- straightforward
- the straight and narrow idiom
- transparency
- upright