The difference is quite simple: confidant is a noun (meaning "a person in whom you confide things"), and confident is an adjective (defined as “having confidence”). You may well be confident in your confidant, but you would not be confidant in your confident.
CONFIDENT definition: 1. being certain of your abilities or having trust in people, plans, or the future: 2. being…. Learn more.
confident completely sure that something will happen in the way that you want or expect: I'm confident that you'll get the job. The team is confident that they will win. Confident is a stronger and more definite word than sure and is more often used in positive statements, when you feel no anxiety.
If you are confident about something, you are certain that it will happen in the way you want it to. I am confident that everything will come out right in time. Mr. Ryan is confident of success. I can confidently promise that this year is going to be very different.
- having strong belief or full assurance; sure: confident of success. 2. sure of oneself and one's abilities, correctness, or likelihood of success; self-confident; assured. 3. excessively bold. 4. Obs. trustful. Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc.
Feeling or showing certainty about something; self-assured. (Of a statement or prediction) Expressed with conviction; very likely to be true. "She walked into the room with a confident stride, ready to face any challenge." (Common in novels depicting strong characters)
confident is an adjective, confidently is an adverb, confidence is a noun: He was confident that he would get the job. He walked confidently into the room, prepared for the interview.