On the Eve of the Wedding, She Died Under the Hairpin I Gave Her

On the eve of the wedding, I couldn't help but secretly visit my fiancée. Unexpectedly, I was involved in the whirlpool of fate, and my life could no longer be peaceful. I opened the door and she was lying on the bed in her wedding dress, with the silver hairpin I gave her inserted in her chest. The maid identified me as the murderer. I was sentenced to death. On the eve of the execution, someone sent a letter. Inside the envelope was the blood-stained hairpin. There were only four words in the letter: Get married tomorrow. I'm going to be questioned and beheaded, so why are we getting married? Married to whom? Going to the underworld to get married?