SPECULATION What girl?

You mean hand over his little sister.....Rey Solo

Its possible.

 

Cousin, you mean.

 

No, that would make his uncle very sad man.



....say that again

 

it probably doesn't work from the timeline as it seems pretty clear that Ben fell when he was 22-23 years old when Rey had already been on Jakku probably more than five years.

in the novelization it is implied that Rey has seen Ren in her dreams. stands to reason he has possibly seen her too.

a close watch of his behavior in TFA shows that he hides things about her from Snoke: he picks her up instead of getting BB-8 (in fact, he literally goes looking for her on Takodana), he doesn't tell Snoke that she is the awakening they felt in the Force even though he's definitely got his suspicions. he also offers to train Rey rather than do as Snoke asked and bring her to him for what's implied is an unpleasant intention.

he's not exactly subtle about it, but he's got his own agenda going on through the whole movie.

my guess: they have a bond in the Force (the "mysterious connection"); he's more quickly aware of it because he's grown up steeped in his own powers whereas she is barely discovering her own.

the timeline as we know it right now suggests they can't have known each other in any other way.
that could change of course, but for the moment, this is the information we have.

either way they have been described as two parts of a whole repeatedly; a broken circuit, yin yang, Dark and Light. so my guess is it's the Force that's shoving them together to bring about this balance that the galaxy so desperately needs. as a side note, i doubt they will accomplish that by destroying each other.