vow, swear, pledge
誓 centers on a formal, binding declaration: making a vow, swearing an oath, or giving a pledge. The idea is a spoken commitment that carries weight.
誓 combines 折 (break, bend) and 言 (words), suggesting words that are firm or unbreakable, i.e., a vow. The exact historical development of the 折 component is uncertain, but the combination is well established.
The top part 折 looks like an axe (斤) cutting something, and the bottom 言 is words. Imagine cutting words into stone to make an unbreakable vow.
For セイ, picture a solemn ceremony where you say your vow: 'say' -> セイ, and your words become a binding pledge.
to swear; to vow; to take an oath; to pledge
oath; abjuration; pledge
oath; vow; pledge; covenant
(religious) vow
written oath
oath; vow; attestation; solemn pledge
Hippocratic oath
Charter Oath (of the Meiji Emperor); Five-Point Imperial Covenant; Imperial Oath of Five Articles
vows of religious orders
to swear falsely
perjury; false oath
joint affidavit
affiant (person who executes an affidavit)
affidavit
administration of an oath
(written) oath
sworn statement
New Year's resolution
Buddha's great vows
to vow to oneself; to promise oneself