How to convert text(with html tag) to XML -WordprocessingML?

Question

I have a string variable. I want to convert it in WordprocessingML(kind of XML). I can convert if I have only string variable(static string) but everytime value of string variable is different. I have tried by didn't get any logical idea.

Example:

Dim strData As String
strData = "This is <b>Bold</b> Text. This is <i>Italic</i> Text"

WordprocessingML (kind of XML) conversation:

<?xml version="1.0"?>
<?mso-application progid="Word.Document"?>
<w:wordDocument
xmlns:w="http://schemas.microsoft.com/office/word/2003/wordml"
xml:space="preserve">
<w:body>
   <w:p>
      <w:r>
         <w:t>This is </w:t>
      </w:r>
      <w:r>
         <w:rPr>
            <w:b/>
         </w:rPr>
         <w:t>Bold</w:t>
      </w:r>
      <w:r>
         <w:t>Text. This is </w:t>
      </w:r>
      <w:r>
         <w:rPr>
            <w:i w:val="on"/>
         </w:rPr>
         <w:t>Italic</w:t>
      </w:r>
      <w:r>
         <w:t>Text</w:t>
      </w:r>
</w:p>
</w:body>
</w:wordDocument>

In my case, `strData` can be any string which can have HTML tags for formatting.

Ex:

strData = "This <b>is Bold</b> Text. This is <i>Italic</i> Text"
strData = "<b><i>This is Bold Text. This is Italic</b></i> Text"
strData = "<b>This is Bold</b> Text."
strData = "<b>This is Bold.</b>"

I have tried to use Replace function but it doesn't work in all cases.

Can anybody suggest me how to convert any string in this kind of format?