What is the test for withdrawing a deemed admission?

In the case of Assaly v. Drever [2002] A.J. No. 103 202 A.B.Q.B. 103, action no. 9903 18317 (M.C.) the court considered the meaning of what was said by Kerans, J.A. in Dwyer v. Fox, at paragraph 18 the court said: I understand that to mean that in any case where there is a deemed admission, the party seeking to withdraw the admission must demonstrate to the court that the evidence available about the fact in question is such that the determination of the truth at a trial is the only satisfactory means to settle the issue. This is required whether the failure to reply was deliberate or inadvertent.