"There is this very weird belief that a woman shouldn't ride a horse," Gosaibi says, especially if she is not yet married as "she might lose her virginity".
"It's amazing how a lot of people believe these things," she tells AFP ahead of International Women's Day on Wednesday.
Herself unmarried, Gosaibi, 35, dreams of opening her own stables to focus on "a more gentle" way of training horses than the standard approach in the male-dominated kingdom.
Saudi Arabia has some of the world's tightest restrictions on women.
But change is under way, says Gosaibi, who returned to Saudi Arabia four years ago after more than a decade living abroad.
"I came back and I saw all these women" working as cashiers, in sales and in offices, Gosaibi says.
Since last year, a government plan for social and economic reforms has given more impetus to this trend.
The government wants more women in the workforce as part of the Vision 2030 plan to diversify the country's oil-based economy, and is trying to expand sports opportunities for everyone.
'Part of the herd'
Saudi Arabia last year appointed a princess to oversee women's sports in the conservative kingdom.
Princess Reema bint Bandar al-Saud in February said authorities would begin granting licences for women-only gyms, local media reported.
"Even (in) sport they're really encouraging women, which is a very new thing," Gosaibi says, taking heart that the change heralds a more favourable climate for starting her business training horses.
But the horse trainer, who learned her skills in Britain and the United States, says she has faced resistance -- "especially with my approach" to the animals.
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Horses have been central to Saudi life for centuries, and the kingdom is famed for its strong desert-bred Arabians from which the racing thoroughbreds are descended.
The traditional way of training horses in Saudi Arabia requires "a lot of force" including spurs and whips, she says.
But Gosaibi prefers to take her time, observing the animal and learning to understand the way it thinks until she "becomes part of the horse's herd".
"You need to establish a certain relationship and understanding because the horse needs to trust you," she says, whether you are preparing a horse for show jumping or rodeo.
If she were a man, her unorthodox approach would be taken more seriously, she feels.
'Let women ride'
Many Saudi women are now taking riding lessons, Gosaibi says, "but it's so much more difficult for a woman" with social norms seeking to keep them out of the public eye.
Tradition requires women to cover themselves from head to toe when outside the home, and unrelated men and women are usually segregated in public places such as restaurants.
Women need permission from a male guardian to travel or study, and Saudi Arabia is the world's only country that does not allow women to drive.
Gosaibi's solution: "Let women ride horses!"
Women rode during the time of the Muslim Prophet Mohammed, she says.
Gosaibi keeps two horses at stables in the Red Sea city of Jeddah, where her baseball cap, collared T-shirt, trousers and riding boots contrast with the traditional black abaya robe that normally shields women from public view.
Other women -- as well as men -- use the facility but its owner doesn't want to draw attention to the fact that he welcomes both sexes.
He asked Gosaibi that photographs not feature other visitors or show the name of the stables.
"They don't want it known that women are in this place," she says.
An entrenched system of male domination makes change difficult, Gosaibi says, but progress is happening nonetheless.
"You can't be stuck for ever in these old ways of thinking," she says.
"Women are becoming stronger and they have a voice."