It's sneaky. Romeo trips upon Juliet talking about how she feels about Romeo and then he gets nervous: Shall I hear more or shall I speak at this?
Once he reveals his location, they are in it together. About 5 times, Juliet shares her fear of Romeo getting caught for being there; no doubt she's concerned for her association with him as well.
Of course love is the central agenda of their discussion, but the growing secrecy and sneakiness evolve as she hears the nurse calling and as they make a plan for when they are going to see each other again.
In the play Romeo and Juliet by William Shakespeare, the mood of the balcony scene in Act Two is one of excitement, expectation and a little fear on the part of the audience. In terms of the mood of the characters, Romeo is entranced by having fallen in love with a new girl (having quickly forgotten about the old!) Juliet is both curious and inspired by the new feelings inspired in her by Romeo. The audience however, remains mindful of the extreme danger that Romeo is in - he is ,after all, trespassing not only on another family's property, but also that of a hated feuding one. The audience is in two minds as to mood. One part of their wish is to find out what happens, and for the guy to get the girl - but the other wish is for Romeo to stay safe by not being discovered and caught.