A saint is someone who has been recognized by the church as being holy. Here are some sentences.
Simon Templar was known as The Saint .
I am sad for the tribulations that this saint endured.
"The NFL team that is going to the Super Bowl is the Saints."
the eruption of mount saint Helen was catastrophic for everyone living near the volcano.
You must be a saint!
No, you would not capitalize either word in this sentence
She is a real saint. Saint Patrick drove the snakes from Ireland. He was made a saint after his death.
The Saint in New Orleans
Your mother must have been a saint. How much longer must the saints suffer?
The actual sentence should be 'la fête de Saint Valentin', making the sentence feminine. The same goes for 'la [fête de] Saint-Honoré': it is feminine as a feast, but masculine for 'un saint-Honoré' (sort of cake); 'la [fête de] Saint-Bernard' is feminine, but 'un Saint-Bernard' (a big avalanche dog) is masculine.
Saints were Christian holy people.
A holy person can become a saint.