Meaning: Venus has the highest surface temperature among all planets in our solar system.
Choice of Words: Venus is the name of a planet, hottest means the highest in temperature.
Meaning: This sentence also tells us that Venus has a high temperature, but it doesn't specify that it's the hottest planet.
Choice of Words: **Very warm** means that Venus has a high temperature.
Meaning: This sentence tells us that Venus has a higher temperature than Earth, but it doesn't specify that it's the hottest planet.
Choice of Words: **Hotter** means that Venus has a higher temperature than Earth. **Earth** is the planet that we live on.