Maria's Billionaire Bodyguard

Maria became an undercover agent for the head of the nation and was tasked to pose as the president's daughter to catch whoever threatened the president's family. Brought by the nature of her job, she was given a bodyguard to safeguard her from unseen danger. What she didn't expect was someone of great wealth to assist her in the operation- Zeronis Villan, the one she had an unpleasant encounter within two occasions. One in Morocco where he disguised himself as the 'Black Prince' and bought her when she was auctioned as a high-value prostitute. The second one was in London, where he greeted her with hot kisses and intimate play in bed. She had no idea why he accepted the job and why he's obsessed with knowing her real identity since the first time they met at one of his hotels in England...
How would they work to solve the case together without recalling the incident between them?