Daniel's writes a headline about a would-be Casanova shaking a girl's hand and then offering her a home loan. He feels ashamed that he shook Natasha's hand and thinks that Charlie would've been unbelievably charming. He would have Natasha dreaming about their half-Korean, half-African American babies.
It's worth noting that as a quality, charm helps people feel seen and heard. The fact that Charlie is so charming suggests that he's aware of the positive possibilities of connection, he just chooses to misuse it.