I have a Japanese Roommate and I asked him to spell it out in english from the Japanese text.
He said it reads "M-A-R-T-Y"
From what little he is able to translate for me (he is learning English) it seems that she is quite antagonistic to X.
There is this one scene in the X2 Manga where she invites him aboard her pirate ship and he points out that she has changed and he lists some of her previous character flaws and she shouts in his face that he changed as well (she accused him of being impolite I think) at which point X observes that she is nicer and kinder now. Shortly after another period of banter-she shoots him out of the ships torpedo bay.
As Marty looks at X through the window, her vice commander enters and makes an observation about her behavior concerning X. Apparently somewhere on her ship she has a holographic replica of X that she vents her emotions to-be they sad, happy, angry, depressed, lonely, etc.
Marty promptly punches him into a wall accusing him, "you peaked!"
If I understood my roommate correctly, there is even one scene where the Vice commander told X that Marty likes him but I'll have to check that out again.
In the X3 manga she saves X from getting his head scrambled by a drill by tossing him his armor chips, fighting Bit in the process. There is a scene where she seems to be cowering beside X only to regain her composure, kick X in the side, and proclaim "I can take care of myself!"
When she urges X not to enter Doppler's fortress, X goes anyway and she tells him to come back alive to which he says, "No promises!"
How does she respond to this? by calling him "Stupid!!"
Despite this she does seem to genuinely care for X as demonstrated by the fact that she beats herself up for letting X walk to his death by entering Doppler's fortress.
On a side note, Marty has no reverence for respected officials as she casually refers to Dr. Cain as "Grandpa!"