I agree it would be difficult for Anne to contrive her comments at that moment but I feel (rather than know) she is expressing a sentiment she has believed for a long time and so is spontaneous and sincere—a burst of feeling if you will. It makes me think of Mrs. Smith again and her “elasticity of mind” (Ch. 17) meaning her ability to see the best of a situation despite many adversities. The unhappy ending of their engagement and the unpleasant ending of the Lyme visit did not spoil the entire experience in either case for Anne. I think from the beginning of the novel Anne has been able to see past their engagement’s untimely demise to remember the felicity of their time together in a way Frederick’s anger and resentment would not allow him to do. It is no wonder then that she sees the Lyme situation in the same light. I think Anne possesses more “elasticity of mind” on how she views the past than I previously gave her credit for. (;D)