Guys, how would you react if a girl did this to you?

You were in love with a girl and she seemingly out of nowhere broke up with you. You took a year and a half to get over her, even praying to get over her. Now you are good friends with a stable relationship and have a small thing with another girl. How would you react if the other girl (the ex, the one who you were in love with) pulled you aside one day and told you that she had feelings for you?