When you use Outlook 2010, you usually get one line with Times New Roman font just before your email signature begins.
Is there any way that I can change this behavior?
Yes, you can change this behavior in Word.
How and where you must change it depends on your version of Outlook and whether or not you have the same version of Word installed as well.
Changing the settings in Word
If you are using Outlook 2007, Outlook 2010 or Outlook 2013 and your version of Word matches your version of Outlook, then you can make the change from within Word.
Open the Options dialog in Word
Office logo at the left top > Word Options
Word 2010 and Word 2013:
File > Options
If your version of Word and Outlook don’t match, use the HKCU Registry:
Value name: Latin
Value type: REG_SZ
Value: proportional font name, size, fixed-width font name, size
Example value: Arial, 10, Courier New, 10