Why does Juliet say to Nurse that her life is troubled and full of sin in Shakespeare's Romeo and Juliet?

In
Act 4, Scene 3, just afterand Nurse finish picking out her wedding
clothes, Juliet excuses the nurse, sending her away by
saying:

I pray thee leave me to myself
to-night,
For I have need of many orisons[prayers]
To move the heavens to
smile upon my state,
Which, well thou knowest, is cross and full of sin.
(IV.iii.2-5)

The reasons why she says this are two-fold.
The main reason is that, per 's instructions, she needs to dismiss
her nurse so she can drink the potion in private. That way everyone
in Juliet's household will believe her death is legitimate so that
her and Friar Laurence's plan can be effectively carried through. We see...

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