Sorry I'm not really not sure but I'll try and find out
It reveals that she wants a love for the ages. She wants him to prove his love for her by giving up everything willingly without a second thought for her. To just be satisfied being with her rather then having his family and wealth
The olden term "thy" means you or your. for example: thy will be done.
so thyself then means yourself.
I hope this helped :)
