The three certainties

A trust will be valid only if the three certainties are present i.e. certainty of words, certainty of subject, and certainty of objects.
 
1. Certainty of words

• There is no need for a settlor to use the word "trust" in order to constitute a trust; it is enough if the words used in the instrument clearly establish an intention to create a trust.
• The words must be imperative and not merely a request i.e. precatory words.(Re Adams and the Kensington Vestry)

 2. Certainty of subject matter

• Where the property subject to the purported trust cannot be identified there will be no trust.  (Sprange v Barnard).
• Where the beneficial interests to be taken by the beneficiaries are not certain, the trust will a resulting trust for the settlor (Boyce v Boyce).

 
However there is no uncertainty in the following cases:-

• Where the trustees are empowered to determine the beneficial interest to be enjoyed;   
• Where the court is able to apply the maxim "Equality is Equity", and divide the property into equal shares.

3. Certainty of objects

The objects of a trust must be certain i.e. a trust will only be valid if it can be said with any certainty that any given individual is or is not a member of the class of beneficiaries. Generally, trusts which fail to meet this requirement are void for uncertainty.

Charitable trusts constitute an exception to this rule. However, such trusts do fail if the gift in not exclusively for charitable purposes (Re Astor's Settlement Trusts).