When will a will be set aside for mistake induced by fraud?

In Feeney, the learned author states: The so-called doctrine of suspicious circumstances does not apply to mistake and the elements of fraud have to be proved. When it is established that the testator was told a lie which motivated a disposition of property in a manner that affected true testamentary intention, then the will, or part of it, will be set aside for mistake induced by fraud.[10] [Footnote omitted] And further: Furthermore, in Kennell v. Abbott it was suggested, at 808, that “a false reason for a legacy is not in itself sufficient to destroy it; it must be that the legacy would not have been given if the fraud had not been practised.” Thus, if there are other motives for the gift, the legacy will stand despite the fraud. For example, a bequest to illegitimate children that the testator thinks are his own should stand, because it can be said that love and affection must have also affected the testator’s intention to provide for the children and that, therefore, the fraud was not the sole motive or inducement for the legacy.[11] [Footnote omitted]