+2  A: 

Are you setting the character encoding correctly?

try this:

mimemessage.setText(s6,"utf-8");

you may need utf-16, cant remember what char set hebrew is on off the top of my head.

try here http://www.i18nguy.com/unicode/codepages.html

Andrew Bullock
UTf-8 and UTF-16 are encodings, not charsets. Both support all Unicode characters (and thus for all practical purposes, ALL characters)
MSalters