another question how i can know one word that worth or not ?

[DnArab.com]

Hello,

first sorry if i make noise to ask new question but i am new in domains business so i need lot of information and help from you

now i have big list for one word english and spanish and germany
verb and name
how i know that the one word domain is worth or not ?
via check if com net org info is taken or not ? or how ?
my big list i have for .com and .net

can you help me pls

Big thanks for all will answer