na-adjective, noun
completely honest; downright honest; straightforward
Emphatic form of 正直 (honest), meaning thoroughly or perfectly honest; often used to describe a person's character or a straightforward statement.
彼は真っ正直な性格で、嘘をつくことができない。
He has a completely honest personality and cannot tell a lie.
真
To be perfectly honest, I'm against that plan.