beswear

verb

1. (transitive)To swear by; swear about or regarding; swear at or to; promise

   “Some masters of the art take a pure child and set him in their lap, then lift his hand up and let him look into his nail, and beswear the child and the nail with a great adjuration, and then speak in the child's ear three unknown words, whereof one is Oriel, the others I withhold for fear of offending.”

   “Thereupon they met themselves, and then peace was talked over, and this was the matter agreed on, that the kings beswore each other brotherhood and settled peace between them while they should both be alive; …”

   “Abraham beswore his servant, Eliezer, by putting the latter's hand under his thigh.”

   “I beswear you that you should be struck in your pericardium by the lance of the mighty [Qitaros], who is ruler over demons, dēvs and liliths.”

   “But if you will beswear what / Others think and be my love [...]”