Believable Part 2

More ways to make a story Believable;

Figurative Language

Setting
If your story is set in ancient Rome, using similes like, "She screamed louder than a train whistle" or "The cat purred like a humming computer" would seem out of place.
A great way to give tone is to use similes that match the environment.
Say you're in Egypt. Try something like, "The sky grew darker than a beetle's belly" or "I wish memories were as easy to wash away as sand." (I don't know. I've never actually been to Egypt.)

Characters
Even within a setting, there are different dialects, upbringing, and intelligence levels.
Is a high school student or an art teacher going to say "She smiled quizzically, reminiscent of the Mona Lisa" or "She grinned like the Cheshire cat"?
Keep in mind where they grew up and the education they received.

Reunions

Reunions are tricky to do. How would you act if you met your father after ten years? How about someone you thought to be dead?
First of all, is the character happy to see them alive and well?

Happy
In that case, I suggest tears, hugs, general jubilation, and the desire to never be parted again.

Not so happy
If it's someone you never wanted to see again, I can imagine that several painful emotions would follow. Perhaps anger or fear.

Naturally, the reactions depend on each character's personality.
In Cornelia Funke's Inkspell, the character Dustfinger returns home to his wife after years of being unable to return. When she sees him, she ignores his presence. They both love each other and are thrilled that Dustfinger has returned, but the wife is proud and hates to show emotion or weakness.