What is the difference in usage between them, i couldnt find anything online and правда и действительно have the same definitions.
"Правда" means "truth":
Это правда, что он ее любит?
Is it true he loves her?
"Действительно" means "really", "actually":
Он действительно ее любит?
Does he really love her?
"Право" in this context is a somewhat outdated word:
Я право не знаю, любит ли он ее.
I don't really know if he loves her.
Of course, I've described only the meaning of each of these words, in which they can be applied in a similar context.
In reality, every word in this list has many other meanings and applications.
If you want a short answer and the question means these 3 words in the sense REALLY, here is the answer:
действительно - neutral, правда - colloquial, право - very old-fashioned, hence could be ironic.
But this is relevant only when they mean REALLY.
Правда can be noun = truth, право - legal system, law.