Understanding the Users comprehension, value attribution, and desirability of a feature will inform your roadmap.

Source: https://futurefriendly.team/
Assumption — the act of taking for granted, or supposing a thing without proof.
Hypothesis — something not proved, but assumed for the purpose of argument, or to account for a fact or an occurrence.
The two things that can trip you up most often is an unconscious assumption that masks a problem with your hypothesis or an unconscious bias in who you are testing the value hypothesis on.
Assumption is a general feeling about a business problem. In order to test if it’s true or not one should develop a sound hypothesis (one or many) relevant to the assumption and the business problem.
Template
https://miro.com/app/board/uXjVM2VglUo=/?moveToWidget=3458764614834430189&cot=14
Source: https://www.linkedin.com/pulse/20140707174655-7214044-assumption-vs-hypothesis/

Prototyping is the conversation you have with your ideas.