Well,since most of the PvP assassins have grown smarter, its become quite a pain to play any build that isnt suited to fighting such melee characters.
Anyway,here it is:
16 Illusion (12+1+3)
13 Inspiration (12+1)
4 Fast Casting (3+1)
Ineptitude
Clumsiness
Conjure Phantasm
Images of Remorse
Distortion
Spirit of Failure
Spirit Shackle or Perhaps Accumulated pain.
Res sig
Spirit of Failure and Distortion is great,Its also good when the enemy has been blinded by Ineptitude(which does a nice 140+ damage when at 16 Illusion.)to give you additional energy.
Ineptitue and Clumsiness, typical anti-attack does around 250 damage total.
Conjure Phantasm and Images of Remorse, Degeneration for Warriors Healing Sigs,Assassins Shadow Refuge, and Rangers Troll Ungent,the additional damage from Images of Remorse is also great.It's also helpful for killing other classes.
As of right now,I'm questioning the effectiveness of Spirit Shackles, and whether or not Accumulated Pain,Since its basicly a great spike.
Right now,I'm open to criticism.
As long as its constructive criticism.
T

Moreover, i've already tried it (with the alternates stated above), i haven't found better in Mesmer's skills' catalogue.