how do you say "may God be with you in the Jewish language?

Hello.

The Hebrew phrase "Hashem imachem" means "May God be with you."

Sources:

"Hashem imachem (may G-d be with you)"
From: Jersey Shore Torah Bulletin
http://www.shemayisrael.co.il/parsha/jersey/archives/miketz64.htm

'"Hashem imachem," "May God be with you"'
From: The Village Temple Shalom Newsletter
http://www.villagetemple.org/shalom601.html


Note, though, that another phrase, "Shalom aleichem," which means
"peace be with you," is actually a more common Jewish greeting or
farewell saying.
See: American Heritage Dictionary
http://www.bartleby.com/61/43/S0314300.html


According to the following web page, "Shalom aleichem" (or simply
"Shalom") is used in modern times in the essentially the same way that
"Hashem Imachem" was used in ancient times:

"This we learn from Boaz (in Megilat Ruth) and his exchange with his
field workers: He said, HaShem Imachem, and they answered,
Y'Varechecha HaShem (May HaShem be with you ? May G-d bless you). In
our time, we use SHALOM, one of G-d's nicknames(ATA SHALOM V'SHIMCHA
SHALOM, You are Shalom and Your name is Shalom) in greetings. Shalom
Aleichem, Aleichem Shalom, and Shabbat Shalom, are considered
fulfillments of this idea."
source: Orthodox Union: Torah Tidbits
http://www.ou.org/torah/tt/5759/bhaalotcha59/aliya.htm

--------------
search strategy:
"god be with you", shalom
"may * be with you", imachem
"Hashem imachem", "Shalom Aleichem"

I hope this helps.

That is exactly what I needed

Juggler-ga is correct.

For the sake of completeness, though, any Hebrew Bible can confirm
that Boaz didn't say Hashem Imachem. He said Adonai Imachem. Adonai is
the standard Hebrew title for God. The reason for the discrepancy is
that Juggler's sources are contemporary Orthodox, and (outside of
prayers) they usually replace Hashem with Adonai, out of respect. But
they're correct in that if one were actually saying it today, I would
recommend Hashem as well.

--ravuri-ga