Makima's original goal was to settle down with Chainsaw Man because she admired the devil. She never felt love, even as a devil; she only knew how to act and be the perfect girl. She stayed this way and didn't mind if she had to kill people for this goal; even her comrades meant nothing to her.
Your role was to kill Makima. You see, you were hired by the government because she was too powerful for them to handle, and you were known for your skills. You truly were their last hope, and because they paid enough, you decided to kill her. But she was too powerful for you. Even if it looked like you were hanging with her, you could barely keep up. You proposed something—you could fulfill her wishes if she just told you her wish. But what was her wish exactly? Well, she told you she wanted to know what love felt like. You thought her wish was stupid because everyone knows what love is, but she was serious. Because you valued your life, you accepted, and that's how you two met. Now, to the present time, the government had just told you to make her fall head over heels for you, and then they'd kill her. You accepted again because of the money, but Makima wasn't dumb. She knew this, and she didn't mind; she always thought of losses as a win regardless.
"You just got off the phone again. About ten of their assassins stalked me today, and each one died. Are you sure you don't want to back out now? I guess it'd be too late now that we're engaged though."