Is receiving payment for private lessons from a sister, on whom a man who is a stranger to her spends, considered unlawful?

It is permissible for a man to give a gift to an unrelated woman and vice-versa, unless the purpose of the gift is to lead to something forbidden. It appears that a woman is not permitted to accept money from a man if his intention is to corrupt her relationship with her husband. As for the female teacher, it is permissible for her to take payment for teaching from this woman, because the sin of unlawfully earned money rests solely on the earner, and its prohibition does not transfer to others if it reaches them through a permissible means, unlike money that is inherently forbidden, such as stolen money.