Unfortunately you can't. Take everything they say with a pinch of salt if they are strangers.
How Do I Know If Someone Is Lying To Me Over Text? And Over The Phone?
You would never no but it is very unsafe for you to me text someone you don't no a lot of ppl ask me for my cell phone number but I just say I don't have one
Can you? I don't think you can unless you contact a professional and expert who can help you detect that. Here is Smith who has helped me detect a cheating spouse, you can contact him on gmail via his username( Williamsdhackghost at gmail..com).. I'm sure he'd help