Orion by Ruby Lionsdrake

Tattooed, muscled, and fierce, they look like felons, but these highly trained agents are humanity’s protectors, the only ones standing between Earth and the threats of the galaxy. They are the Star Guardians.
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A born geek, Juanita has dreamed of exploring the stars for as long as she can remember. Getting kidnapped by slavers from another planet? Not so much. If she’s lucky, she might be able to convince the hot guy protecting her from the others to help her escape.
A bounty hunter allied with the Star Guardians, Orion is undercover on the slavers’ ship, plotting to end their kidnapping trips to Earth. He didn’t expect to meet someone as funny, sexy, and determined as Juanita among the victims. He wants to protect her from the thugs molesting her, but that could blow his cover and jeopardize his mission. He must choose between keeping her safe and dooming Earth to be a target for slavers forever.