swear on (one's) mother's grave

To make a very serious, solemn pledge, especially that one is telling the truth. Janet has sworn on her mother's grave that she wasn't the one to betray me, and I believe her. I swear on my mother's grave that if I have a chance to help your campaign, I will.

Common Names:

Name	Pronounced	Usage
Edyta	e-DI-tah	Polish
Sakineh	-	Persian
Ramona	[rə'məunə]
Menelaus	-	Greek Mythology (Latinized)
Astman	['æstmən]
Mosi	-	Eastern African, Swahili