surely

At a slow or incremental pace but making steady, dependable progress. I've been writing my thesis slowly but surely—it will probably take me all year to finish it, but it's getting there! A: "Hey, how's the new novel coming along?" B: "Ah, slowly but surely!"

slow but unstoppable. Bob's progress on his novel was slow but sure. Nancy is finishing the paint job on her house, slowly but surely.

Gradual or plodding but certain to finish, as in Slow but sure this book's getting written. This idiom was first recorded in 1562, although the idea is much older. A related phrase appears in the proverb slow and steady wins the race, which is the moral of Aesop's fable about the race between a tortoise and a hare, which stopped to nap during the race and therefore lost.