Folks, stop crashing Sabrina's dates! I can totally see why people would want to date her.
She has an exotic, striking beauty, and is a powerful trainer shrouded in mystery. There's nothing in the games to suggest that there is anything negative about Sabrina, she is a spiritual yet shy girl who will take pictures with you in HGSS.
I noticed that nobody had any objections to Blaine getting a date. If Sabrina is no good because she worked for Team Rocket in the manga, then Blaine should be out too, as a top Team Rocket Scientist who experimented on Mewtwo. He does eventually change sides but so does Sabrina. Adventures is the darkest of the canons, where every other gym leader and the elite four was involved in criminal activity at one point.
You can just as easily cite the Electric Tale of Pikachu manga, where Sabrina is a sweet and altruistic helper.
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The whole point of the anime episodes where Sabrina appears is that she was a lonely girl, struggling with incomprehensible powers. She abused her powers to try to manufacture friends. When she lost her sadness thanks to Haunter, she no longer needed to keep the magical doll for comfort and released everyone that she had trapped. She is last shown standing with her parents that loved her, waving goodbye to Ash and his friends, ready to lead a normal life. In all canons Sabrina is somebody who is either good or shows the capacity for good and finds redemption by the end.
I think Sabrina in the anime has more in common with the little girl Molly from the 3rd Pokemon movie Spell of the Unown. Molly tried to stay in an artificial world and make a family for herself. But she wasn't bad, she was just scared and confused. She too grows up despite so much loneliness, and does the right thing eventually.
Sabrina Is no worse than anyone and is totally worthy of love.