Hello, your code should good, I don't understand why you it doesn't work.
try to debug it with print like that :
returnResult = false;
local name = GetSpellInfo(114250);
local _, _, _, count = UnitBuff("player", name);
if count and count >= 4 then returnResult = true; end
print(tostring(returnResult) .. " - " .. tostring(count) .. " - " .. tostring(name))