Learn Portuguese (Portugal): Os quadros têm corações.

Words ending in -ão, like coração (heart), don't just add an "s". The most common rule is to change the -ão ending to -ões. This is why coração becomes corações. You will also see this in words like lições (lessons) or emoções (emotions).

Why is there an accent on the word têm?

The circumflex accent (the "little hat") is used to show that the verb is plural. Tem without the accent means "has" (singular), but têm with the accent means "have" (plural). Because os quadros is plural, we use têm.

Does the word quadros always mean "paintings"?

Not always! Quadro is a flexible word. It can mean a painting, a picture, a picture frame, or a board (like a school blackboard or whiteboard). In this sentence, "paintings" or "pictures" makes the best sense.

Does the tilde (the squiggly line) move when coração becomes corações?

Yes, it does. In the singular word coração, the tilde sits over the "a" to make the -ão sound nasal. In the plural corações, the "a" is replaced by an "o", so the tilde moves to the "o" to keep the vowel sound nasal.