Detect The Form Of A Letter "Character"?

Almost each letter of my mother tongue (Arabic) has two or more forms to be written with, due to its position (At the beginning, middle or end of a word) and what are the two letters before and after it, however, I've been trying to figure why when I type something in a textbox and use the AscW method to get the character code, it returns a code for the same character but not of the same form, which means:

If I type a word starting with the letter above, the letter would be in the initial form (its Unicode is &HFED3 = 65235) , but when I use the AscW to get the code of the first character it returns the code (&H641 = 1601) of the same letter in actually none of the previous forms but apparently in the isolated form (&HFED1 = 65233).I've also tried to convert the default encoding to the Unicode's but had no accepted result and no solution through reading the two Unicode bytes (which had to be [211, 254]).

P.S. I tried something else:

TextBox1.Text = ChrW(&HFED3)

Msgbox(AscW(TextBox1.Text(0)))

to check if the problem is the AscW method, but it worked just fine, I have another idea running through my mind but I'm still not sure about it .So, is there any way to detect the actual form of a Unicode character?