Mr Mews Gives Mrs Snodgrass One Last Chance

 "Dear Mrs. Snodgrass.  I don't mean to be a bother, and please understand that if I don't hear from you after this third and final attempt to engage you, I shall resign from my efforts to meet with you.  I hope you don't view my persistence as untoward but as eager to make your acquaintance.  Yours, Mr Mews."   

There.  That should do it.

Now to address the envelope-

C'est fini.