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
Cynthia	['sinθjə]
Ffraid	-	Welsh
Calypso	kə-LIP-so (English)	Greek Mythology (Latinized)
Kendrick	['kendrik]
Merob	-	Biblical Latin, Biblical Greek
Kearney	['ka:ni]