Custom Validation message for New Item in SharePoint List

Hi,

I have created a custom list in Ms SharePoint 2010. The New item form in the list has been designed using InfoPath forms.

I have attached validation for the custom fields in New Item form. However, the validation error message displayed on saving the New Item form is OOTB Ms SharePoint message. The message is not friendly. I am looking for help to display a friendly message while validating New Item form in custom list. Any help in this regard will be appreciated.