Alice and Bob are discussing their recently ended short relationship. The ending of the relationship was instigated by Alice.
Bob indicates that he thinks it is a shame the relationship ended.
Alice observes "But you don't love me, Bob".
Based on information gleaned from less carefully worded discussions during happier times, the man knows that whether he loves her or not at this early stage in the relationship is unimportant to the Alice, and so concludes this is a rhetorical device.
As such it is very effective in that it acts to confuse the discussion and results in him being unable to respond in the affirmative.
Bob is forced to admit that, no, he does not love her.
Bob knows that pursuing the point further by indicating that he knows this is unimportant to her leaves him in the weak rhetorical position of saying that he knows her better than she knows herself.
And, so with that, the immediate discussion is concluded.
Is there a word or phrase to describe this type of rhetorical device; that wins a discussion via an implied false premise?