In "Casino Royale", Ian Fleming introduces Vesper Lynd as the first "Bond Girl". The two meet at the hotel bar, and Bond immediately falls for her. She becomes Bond's partner in their quest to take down Le Chiffre, but the two are not only connected through their espionage. Their significant romantic involvement becomes a main focus of the story, interrupting their concentration on the mission.
"They got in the way and fogged things up with sex and hurt feelings. " - Casino Royale
It's noted here that Bond prefers not to be distracted by romantic relationships when working in the field, but Vesper quickly becomes an exception. She begins to take advantage of Bond's weakness by seducing him to let his guard down. Realizing his sexual desires, she begins using them to control him. Bond is entirely blinded by his attraction to her, and cannot see through the guise she creates to fulfill her mission. Vesper knows this is his achilles heel, and exploits it. After the two are rescued from Le Chiffre's capture, Bond desires to stop playing the great game so he can settle down with Vesper. This indicates that he has let his guard down entirely, and sees her as a purely romantic relationship. Unfortunately for him, Vesper never felt the same way. What Bond thought was a passionate, mutually beneficial partnership was strictly a business venture for Vesper. Only she doesn't realize the complete nature of their situation until the scene at the hospital. When she finally sees the extent of Bond's admiration for her, it is too much to handle, as her suicide proves her remorse. Fleming uses this as a tactic to enhance the depth of his novels. Though the sentences on the page may be short and simple, he uses them to create a deeper symbolism that can be found between the lines.