Adding Conditions in Page Customization

Dears,

I am trying to achieve the following thru page customization.

If "PERPETUAL_TERM" = TRUE, then another field(custom) on the MA should become a mandatory entry.

I tried the as seen in attachment, but not able to achieve the expected result. Am I doing something wrong or I should follow the scripting method to achieve this.

Thanks a lot

Arahanth