Dear Ing,
I am very flattered that a lovely young lady like you has expressed an interest in an old guy like me, (who had his 73rd Birthday yesterday), but I have to tell you that I have recently started seeing a lady I met on this site, so I regret that I am unable to make any new contacts at this time.
I would like to thank you very much for your interest and to wish you the best of luck in finding the right man for you, who I hope will love and take care of you as you deserve.
Best wishes and take care!
Peter