Convert string to Bool

Question

I am attempting to use a if - else statement that will change the users input options on the backend.  For example, in the drop down menu the data entry person can choose Fire-Truck...however on the backend (and routing purposes I need it to read differently)  So I want to use
[code]
If userentry.text = "Firetruck"
userentry.text = "Ford Truck to Put Out Fires"
[/code]

However this gives me an error of unable to implicitly convert from string to bool.  How does this need to be modified or re-written even so that the conditions I need to meet can be met?