Both can be nouns, both can be verbs. Effect means “result” Affect means “to influence.” Your training in writing will have an effect on your performance in editing. Class participation will affect your grade.
All mean “to make secure or certain” “assure” is used in relations to setting a person’s mind at rest. Harold assured Susan that everything would be fine. The company has insured the staff. New policies ensure greater participation.
Imply means to suggest Infer means to make a suggestion or draw a conclusion These figures imply that our company is going under. We inferred from the figures that we should all start looking for new jobs.
A principle is a basic rule or law A principal is a school office, or the “first” or “primary” of something Auburn’s policies are based on sound principles. The principal’s principal occupation is administration.
Their is a possessive pronoun There is an adverb designation a place They’re is a contraction of “they are” Their new dog drools a lot. There are a lot of dogs that drool. They’re going to buy their dog his own towel.