たしかめる
to check, to make sure of
You have written it and you believe it is right, and believing is not the same as being certain. The same Ta たし as 確か, who can check it if you want it in writing. Read it again: たしかめる.
確か たしか on its own hedges, fairly sure. 確かめる is going and making it certain.
This is one of 1,500 words in Emaki, a free spaced repetition trainer with a written mnemonic on every card.
Study 確かめる in EmakiFree, no account needed. Your progress stays in your browser.
Emaki is not affiliated with, or endorsed by, Kaishi 1.5k or its authors. The word, reading and meaning come from the Kaishi 1.5k deck, used with their permission. The mnemonic, the note and the kanji breakdown are original work, published under CC BY-SA 4.0.