Assume (verb)
to authenticate by means of belief; to surmise; to suppose to be true, especially without proof
“We assume that, as her parents were dentists, she knows quite a bit about dentistry.”
Assume (verb)
to take on a position, duty or form
“Mr. Jones will assume the position of a lifeguard until a proper replacement is found.”
Assume (verb)
to adopt a feigned quality or manner
Assume (verb)
to receive, adopt
Assume (verb)
to adopt an idea or cause
Surmise (noun)
Thought, imagination, or conjecture, which may be based upon feeble or scanty evidence; suspicion; guess.
“surmises of jealousy or of envy”
Surmise (noun)
Reflection; thought; posit.
Surmise (verb)
To conjecture; to posit with contestable premises.
Wiktionary