What is the significance of Romeo asking Balthasar whether he has "letters from the Friar"?

Romeo is looking for any important news about Juliet while he serves his exile in Mantua. It would probably be correct to assume the Friar would act as a surrogate in the delivery of letters between Romeo and Juliet. The Friar also promised he would eventually attempt to reconcile the situation by announcing the marriage and begging the Prince for a pardon. Of course, it's way too soon for that to happen, but the ever-impatient...

Romeo is looking for any important news about Juliet while he serves his exile in Mantua. It would probably be correct to assume the Friar would act as a surrogate in the delivery of letters between Romeo and Juliet. The Friar also promised he would eventually attempt to reconcile the situation by announcing the marriage and begging the Prince for a pardon. Of course, it's way too soon for that to happen, but the ever-impatient Romeo is looking for any bit of news from Verona. In Act V, Scene 1, Romeo has just had a dream where he received good news. He says,

If I may trust the flattering truth of sleep,
My dreams presage some joyful news at hand.
My bosom’s lord sits lightly in his throne,
And all this day an unaccustomed spirit
Lifts me above the ground with cheerful thoughts.

He also foreshadows his death in this short speech as he says Juliet found him dead and tried to kiss him back to life:

I dreamt my lady came and found me dead
(Strange dream that gives a dead man leave to
think!)
And breathed such life with kisses in my lips
That I revived and was an emperor.

This event does happen in Scene 3 but, unfortunately, Romeo has already taken a deadly poison when Juliet kisses him.

Balthasar's news is not from the Friar. Instead, he tells Romeo that Juliet is dead and that he has seen her taken to the Capulets' tomb. Rather than send his letter about the plot to fake Juliet's death with Balthasar, Friar Laurence sends Friar John with the letter, but he is delayed by a plague threat. The all-important news does not reach Romeo, as Balthasar arrives first with the "ill news" of Juliet's supposed death.