The phrase "a rationale for her" is correct and usable in written English.
It can be used when explaining the reasoning or justification behind a decision or action related to a female subject.
Example: "The committee provided a rationale for her promotion, highlighting her exceptional performance and leadership skills."
Alternatives: "a justification for her" or "a reason for her."
The first lady obviously loved clothes, and the media quickly got the idea that she was not going to be stuck on one or two designers and almost as quickly developed a rationale for her ever-changing wardrobe.
Elizabeth Edwards, wife of former Senator John Edwards, was a notable exception when she told Salon.com last summer that Mrs. Clinton was "just not as vocal a woman's advocate as I want to see" and relied too much on her sex as a rationale for her candidacy.
Clinton needs to lay out a rationale for her relevance to the future electorate of a rapidly changing country.
During an interview at home, Carol also gave a rationale for her approach to crying: It was said, you shouldn't let babies cry...so they will build up a basic sense of trust at the beginning....If Sara cries, I can not really endure it.
Because the Winchesters' stories, as individuals and as brothers, have been all over the map, every single fan comes up with "their" backstory and interpretation, and each can come up with a rationale for his or her likes and dislikes.
Similarly, the crosstalk between the vascular endothelial growth factor (VEGF) receptors and HER receptors provides a rationale for combining HER-2 kinase inhibitors with anti-VEGF antibodies (for example, bevacizumab) or small molecule VEGF receptor TKIs [ 63, 64].
Candidates don't have a rationale for attacking her directly, except to claim that the agency would improve if they were elected.
The disabled student (probably encouraged by an administrator who disliked the professor and wanted a rationale for disciplining her) complained to the university's disability enforcer (Office of Diversity and Inclusion), which ordered the faculty member to come to its office for an investigatory meeting.
Crosstalk between estrogen and HER receptors provides a rationale for combining antiestrogens with HER targeted therapies.
"Sometimes," she said, adding a final rationale for her idea, "I think you have to have some compassion".
