In order to deal with a situation or a person, you must take some action. Dealing with a person might involve punishment of some kind. Deals with means to be concerned with. For instance, your English teacher might say that the lesson today deals with nouns.
Ex: Employees must obey their boss's orders without questioning them. He will deal harshly with anyone who disobeys.
Ex: Stephen Frey's autobiography, A Million Little Pieces, deals with his journey through addiction to recovery. It is unfortunate that several details in the book are lies.
You might say to your friend who doesn't know what to do about a problem, "Just deal with it!" This generally happens after you've listened to her complain for some length of time. You could also say this to someone who disapproves of something you have done. If you don't care what she or he thinks, they'll just have to get over it.
Ex: Marty's friend, Jeff, didn't like his decision to go to the Paul McCartney concert. Marty went anyway, so Jeff will just have to deal with it.
Fix means to repair or mend. Fix can also mean to make firm or stable.
Ex: The jeweler used superglue to fix the rhinestones firmly in place on his customer's necklace so she could wear it to her daughter's wedding.
Ex: John broke a tooth when he bumped into another player during a soccer match. His dentist fixed the tooth so no one would know it had been broken.
If someone says that a game is fixed, he means that someone has paid a fighter to lose a match or a team to lose a game. It's considered cheating and anyone who knows this can make the correct bet and win a lot of money. Another meaning of fix is a dose of an addictive substance and often refers to illegal drugs as in a heroin fix.
Ex: Before the big game last weekend, someone paid off the referee to make calls that favored the Canton Warriors. When the league discovered that the game had been fixed, Canton was prohibited from playing in the championship.
Ex: Mary finds it hard to get going in the morning. She needs her caffeine fix before she can even speak to her husband.