Problem in language although DB is UTF8

[shereif]

I created my forum on SMF 2 B4 and when I create a topic in arabic language and preview it it is previewed well but when I post it all arabic text is displayed as smilies and question " ? " marks?

Why is this happening?

نص عربى ؟

[katib]

You have to choose UTF8 at step2 at install ( see the first attached image)
at second and third attached images, you can see there is no problem writing in arabic
لامشكلة في الكتابة بالحروف العربية 

[Rumbaar]

You might have to alter your db's table collation as well to support your utf8 character set.