Then again, no one sanely doubts that it was the right decision.
1721, back-formation from sanity or else from Latin sanus "sound, healthy," in figurative or transferred use, "of sound mind, rational, sane," also, of style, "correct;" of uncertain origin. Used earlier, of the body, with the sense of "healthy" (1620s). Related: Sanely.
Of sound mind; mentally healthy.