You can use the Text component Randomizer to add small variations to how the bot is replying to same questions. 

To add a variation, click + at the top of a text component and add your variations as you would normally do in a text component.

Each text component can support can support a total of 5 variations. You can move between variations by clicking the navigation dots.

To delete a variation, first select which variation you want to delete by clicking on the corresponding dot, then click X to delete the variation.