>
 >
 > >> May be ConTeXt experts would have better suggestions, till then you
 > >> may want to look at the fake bold option in simplefonts -
 > >> 
http://wiki.contextgarden.net/Simplefonts#Faking_italics_and_bold_fonts
 > >
 > > Thanks for your advice.
 > > Unfortunately I did not manish to work with this font by 
simplefonts. I use the following simple setup:
 > >
 > >
 > > \definefont[arabic][file:bliblablup_0.ttf*arabic at 15pt]
 >
 > \definefontfeature[fakebold][extend=1.1]
 >
 > \definefont[arabic][file:<fontname>*arabic,fakebold at 15pt]
 >
 > > \starttext
 > > \arabic\setupalign[r2l] ٱللَّهُ لَآ إِلَـٰهَ إِلَّا هُوَ ٱلْحَىُّ ٱلْقَيُّومُ
 > > \stoptext
 > >
 > > How can I get these "fake bolds" with this setup? Or is it 
absolutely necessary to use Simplefont for these fake-bolds?
 >
 > The feature is unrelated to simplefonts.
 >
 > Wolfgang

Thanks Wolfgang, but that does not seem to work with this font. See 
attachment, the font is wider, but not bold.

++++++++++++++++
\definefont[arabic][file:bliblablup_0.ttf*arabic at 15pt]
\definefont[arabics][file:bliblablup_0.ttf*arabic at 15pt]
\definefontfeature[fakebold][extend=1.2]
\definefont[arabic][file:bliblablup_0.ttf*arabic,fakebold at 15pt]

\starttext
\arabic\setupalign[r2l]
ٱللَّهُ لَآ إِلَـٰهَ إِلَّا هُوَ ٱلْحَىُّ ٱلْقَيُّومُ
\blank\arabics\setupalign[r2l]
ٱللَّهُ لَآ إِلَـٰهَ إِلَّا هُوَ ٱلْحَىُّ ٱلْقَيُّومُ
\stoptext
++++++++++++++++

Huseyin