Del. P.J.I. Civ. § 19.8

MUTUAL MISTAKE

If the parties to a contract are both mistaken about an important fact, and if the

mistake involves a basic assumption of the agreement and not merely an incidental

matter, then the contract may be voided. An important fact is one that, in light of

the surrounding circumstances, would affect the decision-making of the parties. The

party complaining of the mistake must demonstrate a reasonable degree of diligence

in discovering the necessary facts before the agreement was made. Finally, the

mistake itself must be shown by clear and convincing evidence.

You may find that the contract at issue is not enforceable only if you find:

(1) that [plaintiff’s name] has shown by clear and convincing evidence that

there was a mistake of fact about [describe the alleged mistake of fact];

(2) that the mistake of fact was important to the agreement between

[plaintiff’s name] and [defendant’s name]; and

(3) that [plaintiff’s name] made a reasonable effort to discover the correct

facts before entering the contract.