Alexander Schmidt, Shakespeare Lexicon and Quotation Dictionary

Assurance, 1) confidence, certain knowledge: “rather like a dream than an a. that my remembrance warrants,” Tp. I, 2, 45. “my a. bids me search,” Wiv. III, 2, 47. “put your lord into a desperate a. she will none of him,” Tw. II, 2, 8. “a. bless your thoughts!” Tim. II, 2, 189. “I'll make a. double sure,” Mcb. IV, 1, 83. “and from some knowledge and a. offer this office to you,” Lr. III, 1, 41. For a. == to make confidence greater: “for more a. that a living prince does now speak to thee,” Tp. V, 108. “for the more better a. tell them that I am not Pyramus,” Mids. III, 1, 21. “for a. let's each one send unto his wife,” Shr. V, 2, 65.
2) that which gives confidence, a) certainty, safety: “jealousy shall be called a.” Ado II, 2, 50. “by this knot thou shalt so surely tie thy now unsured a. to the crown,” John II, 471. “his head's a. is but frail,” R3 IV, 4, 498. “they are sheep and calves which seek out a. in that,” Hml. V, 1, 126. “quite forego the way which promises a., and give up yourself to chance,” Ant. III, 7, 47. cf. take you a. of her == make sure of her, Shr. IV, 4, 92. “by an auricular a. have your satisfaction,” Lr. I, 2, 99 (confirmation).
b) a solemn declaration or promise: “give a. to Baptista, as if he were the right Vincentio,” Shr. IV, 2, 69. “give me modest a. if you be the lady of the house,” Tw. I, 5, 192. “plight me the full a. of your faith,” IV, 3, 26. “if you mind to hold your true obedience, give me a.” H6C IV, 1, 141.
c) a certain proof: “to give the world a. of a man,” Hml. III, 4, 62.
d) a legal evidence: “let your father make her the a., she is your own,” Shr. II, 389. Shr. II, 389 “and make a. here of greater sums,” III, 2, 136. “to pass a. of a dower,” IV, 2, 117. “where then do you know best we be affied and such a. ta'en,” IV, 4, 49. “they are busied about a counterfeit a.” IV, 4, 92.
e) surety, warrant: “you should procure him better a. than Bardolph,” H4B I, 2, 36. “having here no judge indifferent, nor no more a. of equal friendship and proceeding,” H8 II, 4, 17.