Gambit had one of the coolest backstory when I used to read comics.
For the longest time, his background was a secret. The X-men didnt even know his full name. They just knew him as Remy.
In the future, The X-men are dead, betrayed by one of their own.
The Mutant Bishop went to talk to a figure called the "The Witness" who was said to be the last person to see the X-men alive. The Witness' name is Lebeau.
When Bishop Time Travel to the past where he ended up meeting the X-men, when he finally met Gambit, he was shocked as he looked like "The Witness".
Bishop revealed Gambit's last name as Lebeau, and told the X-men that he thinks Gambit aka, the witness is the one that betrays the X-men.
Gambit, upset that Bishop revealed his true name ended up fighting Bishop.
The fight was eventually de-escalated, but Bishop didnt trust Gambit. So even when Bishop became an X-men, and he ends up fighting alongside Gambit, he didnt fully trust him.
Professor X who is also the greatest telepath, was also surprised, as Gambit was able to block him from reading his thoughts.
So for the longest time reading the comics, he was a mystery, you were not really sure whether Gambit could be trusted. Is he a friend or foe of the X-men?
He's also a player that uses women all the time, and as Irony will have it, he finally falls in love to a girl he couldnt touch...Rogue.