make sure, confirm, check, double-check, determine, verify.
percervere
learn, find out, ascertain
Another word for the phrase 'to make sure' would be 'to ascertain'
ascertain, reassure, and maybe to make sure...
The word "ascertain" is a verb. It means to find out something with certainty.
I have yet to ascertain the knowledge required to become a lawyer.
Verb.
cert
The opposite of the word "estimate" is "ascertain." While "estimate" involves making an approximate judgment or calculation, "ascertain" refers to the process of finding out something for certain or determining an exact value.
The word "ascertain" appears on page 112 in "And Then There Were None" by Agatha Christie.
Albert Einstein said: Science can only ascertain what is, but not what it should be, and outside of its domain value, elly judgements off all kinds remain necessary.
Don't know about one word, but a two word phrase that means exactly the same as "weigh" is "ascertain displacement".