Explanation

"But" is used to contrast two ideas.

The first clause shows intent to leave, and the second shows he didn't, so contrast fits best.  

 He wanted to leave but he stayed until the end.

(وہ جانا چاہتا تھا لیکن وہ آخر تک رُکا رہا۔)

Explanation

If she had a chance to travel, she would visit many cities, for example: Paris.

This sentence uses a comma before “for example,” which is grammatically correct.

The colon after "for example" is acceptable for emphasis in some styles.  

It maintains clarity and fluency.

Explanation

He is true to his word 

وہ اپنے قول پر سچا ہے۔

The correct preposition with "true" in this context is "to".

The phrase means he keeps his promises or commitments.

Explanation

His father deals in old cars.

اس کے والد پرانی گاڑیوں کا کاروبار کرتے ہیں۔
"deal in" is the correct phrase when referring to trading items.

Explanation

Sara appealed to the stranger for help.

سارہ نے اجنبی سے مدد کی اپیل کی۔

The correct preposition used with "appealed" in this context is "for" when asking or requesting something.