Sentence:  The warranty that a ship shall sail on a given day must be strictly performed. Thus, if a ship, <WSD>warranted</WSD> to sail on or before a particular day, be prevented from sailing on that day by an embargo, the warranty is not complied with. 
Meaning of the word marked with <WSD> tags:  To give (someone) an assurance or guarantee (of something); "also, with a double object": to guarantee (someone something).