You don’t need to be overly personal, but saying "Relocating for work" or "Settling an estate" explains the urgency without making you sound desperate.
"Similar homes in the area are selling for $[Higher Price]." please buy my house
Investors appreciate knowing the "ugly" parts upfront so they can calculate their ROI. You don’t need to be overly personal, but
Even if the house is a "fixer-upper," clear, well-lit photos (at least 10–15) are mandatory. please buy my house
$[Insert Price] (Note: Mention if this is "below market" for a quick sale).