Shakespeare lived in a time when Jews in England were not well-liked and it is therefore a reasonable question to wonder whether a Jew can in fact trust a Christian with such a crucial plan - one to escape her father, Shylock.
The main focus for Jessica , however, is not the fact that she is a Jew but that she is in love; being Jewish may complicate the matter but Jessica is willing to convert to Christianity anyway - if only to upset and incite her father. The audience, watching this play would have been impressed with her claims that
"I shall be saved by my husband, he hath made me a Christian!" (III.v.19).
Launcelot, a clown, and something of a lazy character"snail-slow in profit" lets Jessica know that, despite her allegiances she is in fact
damned in her very birthright.
Launcelot dislikes Shylock and his Jewishness describing Shylock as “ a kind of devil" and as Launcelot has just been offered a job by Bassanio, Jessica thinks it will be safe to ask him to deliver her letter to Lorenzo.
In Act II.v Jessica and Launcelot have a secret conversation which sparks Shylock's interest but, as Launcelot is now leaving his employ - about which Shylock is very pleased- Jessica is able to distract her father from the real content of the conversation.
In Shakespeare's day it was the Jews who could not be trusted, not the Christians so it would have been more than feasible for Launcelot to be involved in Jessica's plot to escape her father's house.