“Doubt thou the stars are fire;
Doubt that the sun doth move;
Doubt truth to be a liar;
But never doubt I love.”

― William Shakespeare, Hamlet

This quote is from William Shakespeare’s play “Hamlet,” specifically from Act 2, Scene 2. It’s part of a letter written by Hamlet to Ophelia. Here’s a breakdown of its meaning:

1. “Doubt thou the stars are fire;”
   This means “You may doubt that the stars are made of fire.” It’s suggesting that one might question even the most accepted truths.
2. “Doubt that the sun doth move;”
   At the time Shakespeare wrote this, it was commonly believed that the sun moved around the Earth. This line means “You may doubt that the sun moves in the sky,” challenging another widely accepted belief.
3. “Doubt truth to be a liar;”
   This means “You may doubt that truth is truthful,” implying that one might question even the nature of truth itself.
4. “But never doubt I love.”
   Despite all the things one might doubt or question, this line asserts that Hamlet’s love for Ophelia should never be doubted.

Overall, Hamlet is expressing that while many things in the world may be uncertain or questionable, his love for Ophelia is steadfast and unquestionable.