Tokens: The Money of "Love"

As Venture is trying to convince Trier (and himself) that he has successfully wooed Carol, Trier asks, "You are not yet contracted?"  Venture replies uncertainly, "No, she chang'd / Some amorous tokens; do you see this diamond? / A toy she gave me...and in exchange / She took a chain of pearl...These to the wise are arguments of love, / And mutual promises" (p. 463).  Of course, we find out later that Carol has merely exchanged tokens between two suitors and kept nothing for herself.  However, she gives the impression to both that she has entered some kind of "contract" of love.  How do these exchanges and Carol's own question to Venture of, "Because I took your diamond, must you presently bound like a ston'd-horse," complicate the place of objects between lovers?  Can Carol only pursue this kind of play because she is an autonomous woman?