Assuming

/əˈsjuːmɪŋ/

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.”
To take on a position, duty or form
“Mr. Jones will assume the position of a lifeguard until a proper replacement is found.”
To adopt a feigned quality or manner; to claim without right; to arrogate
“He assumed an air of indifference”