You use conditional macros like (if:) and (else:) to control which (set:) macros get called based on the current value of the variable you’re storing the end-user’s answer to your question.
note: You code example doesn’t include how you’re tracking the answer to the “girlfriend or boyfriend” question, so in the following example I will assume that answer has been assigned to the $girlfriend variable. I’m also going to assume that variable can only one of two values, those being “girlfriend” or “boyfriend”.
(if: $girlfriend is "girlfriend")[
(set: $her to "her")
(set: $she tp "she")
(set: $her to "his")
(set: $she to "he")
You can use (naked) Variable markup to inject the current value of those variables into textual content like so…
I see your $girlfriend over there, $she appears to be talking to $her friend Abcdef.