swear to

Also found in: Dictionary, Thesaurus, Idioms.
Related to swear to: swear words
See: vouch
References in classic literature ?
I'd just as soon tell you who I am, though, if you'll swear to keep mum, for I ain't no Phillips, either."
The manner of their swearing is this: they set a sheep in the midst of them, and rub it over with butter, the heads of families who are the chief in the nation lay their hands upon the head of the sheep, and swear to observe their promise.
For instance, people with higher social status can even swear to people from lower social status or vice versa.