I was using Smooth slider and was unable to add HTML tags to the text.

If you are also facing same problem then here is solution which helped me :

Solution : Settings > Smooth Slider. Scroll to Miscellaneous. The first input box says:

Retain these html tags

Write your HTML tag which you want to retain like i wrote <strong> & <br>. 

See attached image.

slidervilla

Note: This solution is applicable to all the other sliders of Slider Villa (Smooth Slider, Pointelle Slider,Roster Slider, Verticalis Slider, Listic Slider, Thumbel Slider,Indexo Slider, Testimonial Slider, Pinwheel Slider, Akkord Slider, Glam Slider)