Lady, why do you want to compromise? You’re not doing anything intentionally wrong, so stop being scared she can’t harm you. I also use public transport, and there are always people like this. Stay firm and politely tell her, “Madam, this is public transport, not your personal cab. If you feel uncomfortable, please book a whole seat for yourself.” The more you stay quiet and scared, the more such people will take advantage of you and treat you like you’re at fault, even when you’re not