Is money taken from a stranger, with their consent and without consideration, for assistance considered unlawful?

If a man pays money to a woman with his consent and without compensation, and there is no lying or deception involved, then there is no harm in her taking it. However, if the money was a loan, it must be repaid unless the lender waives it. One must also be wary of relations between a man and a foreign woman that are not necessitated by a permissible Shar'i need.