So vesper betrayed bond and mathis both in CR, ultimately mathis was innocent ... vesper was duped by Yusuf?
Yes. He worked for Quantum, but pretended to be a regular guy and seduced her and became her boyfriend knowing she had access to government information.
The only betrayal of Mathis, I guess, was to tell the bad guys of his existence so LeChiffre could use his name.
He had given the necklace to vesper just like he had given it to corrine (the Canadian agent). What was Yusuf getting in return? ... vesper was not a british spy she worked for the treasury branch!
But exceedingly high-up if she's sent undercover with 007.
It's not like Yusef will be the only agent Quantum has in operation. Nor that Yusef was necessarily only working one woman at a time.
why does vesper kill herself and give the money to Quantum in CR? If to save bond? how does that garantee his safety ... falling for Yusuf, seems out of character for vesper ... she came across quite intelligent!
Intelligence has nothing to do with attraction.
She saves Bond at the docks after Bond is tortured - saying she'll get the money in exchange for his life. But she still has to betray Bond to do it. She can't live with the guilt of that - especially on top of the way she fell in love with him while her boyfriend was being held to ransom - so chooses to die. He decision to die isn't related to practical decision-making; it's purely emotional.
Also, do you guys think that Yusuf is beaten to a pulp by bond ... albeit alive? Thanks for the help!
No. That's the point of QoS - "The dead don't care about vengeance."