The sun's centre is hot enough, and it is a huge fusion reaction turning hydrogen into helium, and only avoids exploding and destroying the Solar system because of its own self-gravity, which holds it in.
The "huge fusion reaction" is at a very low rate-- only the immense mass and volume of the Sun make it "huge". The core of our Sun (inner 24% of total radius, where ~99% of its energy is produced) has an average power volume of 276.5 watts per cubic meter, or 276.5 microwatts per cubic centimeter. At a 150 g per cubic centimeter, that translates to a power density of 1.84 microwatts per gram. It is sobering to consider that such a minuscule level of power at the Sun's 15.7 million Kelvin core temperature, and its maximum 250 billion atmosphere pressure, would likely be utterly undetectable in any terrestrial laboratory context.
Against such a stellar example, any modest measurable over unity COPs or immodest Q values, especially from cool fusion, are very remarkable.