Perhaps having a look at the quotes from a modern English perspective may allow us to determine whether irony can apply here:
Anne
: "I wish I knew what was in your heart."
Richard:
"I've told you"
Now, given our understanding of the quotes in modern English, one can infer that irony may indeed be a technique that is relevant in this context, since, despite Richard having already told Anne of what is/was in his heart, the latter is still doubtful, which is further demonstrated by the subsequent quote from Anne, being
"I fear me both are false" (i.e.
"I fear that your words and your heart are both false.").
I hope this helps!