Comparison of Default Text against String Input Field

Hi all,

I have recently been playing around with some solutions on a sim on how to compare a users 
input text in a record, to see if the text entered is the same as or similar to the default text normally

auto-filled in the field. and was wondering on some ideas on how to approach this?

For Example:
String Field Default Text: 
"Please fill out the following:
Step 1:
Step 2:
Step 3:"

But say the user enters a few symbols or enters a space:

" Please fill out the following
Step 1: 
Step 2: $$
Step 3:"

I was wondering would predictive intelligence be able to tell me how similar the entered text is compared to the default value? for example: "Text is 95% Similar"?

Would love to hear some others thoughts on checking default text when a user can do small input amounts to bypass easy checks such as: String field -> is or contains -> Default Text.