LGBT: Is it ok to play with someone's feelings when...?

ok before anyone says something mean...i personally do not like it when people play with my feelings. But this girl i use to like back in the day plays everyone that likes her and i want to teach her a little lesson ..like i want to flirt with her and hold her hand and then the next day tell her i have a g.f. but the only reason why i want to do this is because she needs to wake up and realise not to play with anyone..in a way i want to help her come out of her shell of heartbreaker and be a better person but idk if i should do it because i'm not that type of person...like i already did the first steps of kinda giving her clues i like her again but i'm feeling guilty already! should i keep with this plan? And if so what else should i do so she can see i like her and then realise i played her. please dont judge me ..again the only reason i'm doing this is to show her what it feels like when she plays with other peoples feelings