Emphasis:
* "I really love that song!"
* "It's really important to me that you understand."
* "He was really tired after the long drive."
Confirmation or agreement:
* "You're going to the party, really?"
* "Are you sure you want to do that? Really?"
* "Yes, I really do want to go."
To express surprise or disbelief:
* "You're really going to eat that whole cake?"
* "He said he was going to quit his job? Really?"
* "I can't believe you really did that!"
To mean "actually" or "in truth":
* "I thought it was going to rain, but it's really a beautiful day."
* "I don't really care for spicy food."
* "She's really a kind and generous person."
To express a strong opinion:
* "That movie was really bad."
* "The food at that restaurant is really delicious."
* "I really think you should go to college."
To describe intensity or degree:
* "He was really angry."
* "It was really cold outside today."
* "The music was really loud."
As you can see, "really" is a versatile word that can be used in many different ways to convey a variety of meanings.