Wondering if anyone had any tips for trying to remember the differences between all the ways to say indicate extreme certaintay in Japanese. I currently have:
絶対に, 必ず, きっと, 全く, and ずっと
in my heavy rotation and all I can do to progress is proceed to guess each and everyone of them, which I feel defeats the purpose of learning. If anyone can elucidate the differences, I would be ever grateful.
My favorite is てっきり
surely, certainly, without a doubt (used of beliefs that turned out to be wrong) 
Explaining the difference is unfortunately way out of my depth, all I can say is that these are not interchangeable.
Perhaps it’s more productive to change review type to “reveal and self grade” for similar words? Then you can grade it as a pass if you know what it means in general, and save valuable time for other items.
I ran into this problem a lot and still do. I was trying to use the English meanings to remember the Japanese words. I found it useful to look at the Japanese definitions and example sentences to get a sense of how they differ.
Another option is to use AI to get a rough sense of the difference between similar words and to build mnemonics. Just make sure you double check the answers. AI is super sensitive to input variation. Even reusing the same input can give you wildly different answers.
絶対 (ぜったい) – “absolutely, without fail”
• 
Strong assertion, like a rule of nature.
• Example: 絶対に諦めない。 → I will absolutely not give up.
• Focus on obligation, duty, or certainty.
• Example: 宿題は必ずやりなさい。 → You must certainly do your homework.
• Expectation or prediction, not absolute.
• Example: 明日はきっと晴れる。 → Surely, it will be sunny tomorrow.
• Complete negation or emphasis.
• Example: 全く分からない。 → I completely don’t understand.
• Continuity over time.
• Example: 子供のころからずっとピアノを習っている。 → I’ve been playing piano all along since childhood.
| Word | Mnemonic ( memory trigger) |
Story / Image |
|---|---|---|
| 絶対 |
 Mountain Seal: “絶対 lock!” |
Imagine a mountain with a giant red seal  that cannot be broken. Absolute certainty. |
| 必ず | 🏃♂️Homework Stopwatch: “必ず finish!” | Picture a child racing against a ticking stopwatch  to complete homework. Obligation + guarantee. |
| きっと |
 Sun Umbrella: “きっと晴れる” |
Think of opening an umbrella  indoors, yet the sun beams through — hopeful prediction. |
| 全く |
 Ice Cube: “全く frozen” |
Visualize a frozen cube , completely solid, nothing inside moves. Total negation. |
| ずっと |
 Tree Ring: “ずっと growing” |
Imagine a tree growing rings for decades, continuous growth without interruption. |
On top of the advice already given, I’d definitely look through Bunpro’s example sentences for each word to get more of a feel for them