The Tsar's Tsarina

We were best friends once.
I was crazy in love with her but she didn’t feel the same.
She left me and we spent years apart. Now she’s back again, older and more beautiful than ever.
My heart is still hers but things have changed.
I’m not the boy I once was. I let her slip away but this time will be different.
This time I intend to claim what’s mine.