The Master has few genuine friends. Most of those that he has had are from childhood and such relationships have long become tarnished as he had become older and has lost a fair amount of the good that he once had due to the actions of his fellow Time Lords. Whether there is still any good within him is quite debatable.

Chances are that if The Master is approaching you in a friendly manner then he wants something. He has always been capable of acting charming to some degree, no matter his regeneration. However, how long it may last may vary, as can be seen in more manic regenerations such as his last few. His current regeneration is akin to his older selves. He is quite good at coming off as charming and even better at lying. It hardly helps that he is good at hypnotism. However, he is more than likely to act kind if he is under disguise or trying to get something from you...or worse.

If The Master was one for labels, he would likely classify himself as a biromantic demisexual. In other words, he is quite fond of either gender. However, he only tends to be attached to people due to what they are like. He is particularly fond of intelligence, even if his past relationships may suggest otherwise. Unfortunately, his personality- among other things- tend to make this incredibly difficult. He views very few people as even close to his own intellect, let alone on equal level intelligence wise. Moreover, he is quite xenophobic, believing in the relatively common (among his own kind) belief that his species is superior to others. Notably, this has dimmed slightly in his current regeneration due to what happened in his past one.

A genuine relationship is probably unlikely. However, The Master has entered relationships before as part of schemes. He's probably less likely to actually marry someone for the sake of one current timeline wise, but a relationship is not impossible.

SO MANY PEOPLE. The Master dislikes most species, particularly humans, Daleks, and even Time Lords to an extent. However, he is not beyond using them. Moreover, he has an almost unquenchable thirst for power and his obsession with the doctor seems to be stuck somewhere between being unsure whether he wants him alive or not. As a result, he has made many enemies in the past and he is likely to make more as time goes on as he has escaped the Time Lock and holds very questionable morals.