Hi xxx,
After I submitted my resignation letter to my boss this past Monday morning, he discussed with me four times over the course of three days about the possibility of my staying with the company. He advised me strongly not to leave and offered me a great increase in salary. That being said, I still very much desire to join your group, despite this recent turn of events. May I ask you if there is still a chance of receiving a salary increase? Thank you for your understanding and I hope to hear from you soon.