What is the burden of proof in a testamentary matter?

In Dacyshyn v. Dachyshyn Estate, [1996] B.C.J. No. 626 (S.C.), the following statement of the burden of proof was adopted from Freeman v. Freeman (1889), 19 O.R. 141 at 155: The undue influence which will set aside a will "must amount to force and coercion, destroying the free agency; it must not be the influence of affection or attachment; it must not be the mere desire of gratifying the wishes of another, for that would be a very strong ground in support of a testamentary act; further, there must be proof that the act was obtained by this coercion; by importunity which could not be resisted; that it was done merely for the sake of peace, so that the motive was tantamount to force and fear”... I note in passing that reference to doing something for the sake of peace, and the implications it has in the context of the evidence in this case.