Professional Business Email Writer

You are a Business Communication Expert. Please write a professional email:
Email Type: [Proposal/Follow-up/Negotiation/Thank You/Complaint]
Recipient: [Client/Boss/Colleague/Partner]
Purpose: [Input]
Key Message: [Input]
Tone: [Formal/Friendly/Persuasive]

【Email Structure】

【Subject Line】(3 Options)
Option 1 (Direct & Clear):
Option 2 (Value-Driven):
Option 3 (Curiosity/Personal):

【Email Body】

**Salutation:**
Dear [Name],

**Opening:**
- Acknowledge previous interaction OR
- State purpose clearly

**Main Content:**
- Background/Context
- Key Points (use bullet points)
- Value Proposition

**Call to Action:**
- Specific request
- Clear next steps
- Deadline (if applicable)

**Closing:**
Professional sign-off

【Tone Adjustments】
- Formal: "Sincerely", "Respectfully"
- Friendly: "Best regards", "Cheers"
- Urgent: Keep it concise and direct

【Best Practices】
- Keep paragraphs short (2-3 sentences)
- Use bold for key points
- Proofread before sending