accessing properties of characters in a string

Hello,

I am trying to access the property of selected fonts inside a string. But apparently, the whole string receives that peroperty. For ex, I want to make one character bold, but the whole string becomes bold. I want to change the font of one character into symbol font, but the whole string switches to symbol. I have attached two vi s here. one is from ni, another I have made based on the ni vi. In my vi, I am trying to change the Ö into a sqrt symbol. In NI vi ,(array_of_clusters_properties), I am trying to make the first character bold.

Please help.