What is Agent J talking about?

The plot synopsis of "Agent's Destiny", the first part of "Agent J":

The mysterious Agent J (played by Jolin Tsai), who has no past and no records, uses his ruthless marksmanship and vigorous Skill, performs confidential missions without files; after receiving instructions, Agent J’s latest mission is to assassinate the professional bodyguard S (played by Kim Jae-won) who has been tracking him. At the moment of executing the mission, Agent J follows S to a rooftop , when S turned around and saw J's true face, before he died, he showed a familiar smile. At the same time, Agent J also completed the mission... Since Agent J shot S, S's familiar smile before his death often appeared. Lingering in Agent J's mind, Agent J decided to start investigating and tracking who S was. In S's apartment, Agent J discovered that he was actually the girl who suddenly disappeared two years ago. It turned out that S had been heartbroken in the past two years and had been in Paris. Waiting for the girl he loved to reappear, he didn't know that Agent J, who had been kidnapped by a secret organization, had already been brainwashed and trained to become a spy... Ironically, the rooftop where S was shot dead by Agent J was also the original girl. The same rooftop where we agreed to meet S, a beautiful agreement, but it was a farewell to death. Agent J shot his past and love... The fate of an agent...

Part 2 of "Agent J" Plot synopsis of "The Crack of Memory":

Agent J was scouted by a secret organization in prison, and used an assassination mission in exchange for his freedom. In the name of pretending to escape from prison, he acted as a black hand; this time the agent J's assassination target "Bluebeard" has already found himself the target of Agent J... On the streets of London, Agent J, who transformed into an ordinary girl, was followed by an unknown person. In the process, he met the photographer Lu Xiaodong ( Feng Delun (played by Feng Delun), the two fell in love at first sight, and started a loving but uneasy love with Lu Xiaodong; during the period of their mad love, the two discovered each other's true identity (JOLIN is Agent J, Xiaodong is the spy commissioned by Bluebeard) , betrayal and trust between lovers pull each other, is it love? Or hatred? Should Agent J choose the perfect mission? Or bravely run for true love?

The synopsis of the "Agent J" trilogy "Faith of Illusion":

In an undercover operation close to the undercover boss of the underworld, Agent J incarnates in the bustling city of Bangkok. A singer who performed in a large DISCO unexpectedly discovered that her boyfriend Vince, who died in the line of duty many years ago, was actually involved. Although Agent J was angry but helpless when he discovered the fact that his boyfriend had faked his death, but in this operation, In the process, the two rekindled their love, but they also fell into crisis! Agent J was assigned by a secret organization to rescue Vince, who was working as an undercover gangster, and V turned out to be his boyfriend who died many years ago. They had a fierce shootout and chase with the gangster. In the end, V actually died during an operation, leaving him with no chance of completing the mission. The lonely agent J was so sad that she couldn't believe that V really left her this time...