Situation
Someone offers you more food, but you are genuinely full.
Say no appreciatively while keeping the warmth of the offer.
Natural American English
“I’m so full, but thank you—it was delicious.”
Tone
Warm, grateful, and firm enough.
What lands
The appreciation is the important part. It separates declining more food from rejecting the meal or the host.
Try it
Your aunt offers you another slice of cake, but you cannot eat another bite. What could you say?
Reveal a natural response
“I’m so full, but thank you—it was delicious.”
Common mistake: A bare “No, I’m full” can sound final. Add thanks or a compliment when the context calls for it.