i cant answer this 100% but i would think it would have to be Peach. i think he secretly likes her and wants Mario dead so he can have Peach for himself.
No, bowser junior doesn't have a brother. He does have a father: Bowser.
Not likely because Bowser has a crush on Peach
THEY LOVE
Most likely not because he is preocupied by peach but who knows maybe Nintendo will suprise us.
Because Bowser loves Peach so much. But the guy dont know how 2 show love, unfortunally.
Love, obviously. True love... Even though Peach and Bowser must have slept together to have baby Bowser
Yes, he does. In the game Super Paper Mario, it shows that Bowser really does have feelings for her.
Bowser is the Koopa King. In other words, he's a boy. This is best shown by the fact that he is in love with Peach, which is explicitly stated in Paper Mario.
No! She helps Mario save Peach from bowser kidnapping her
As noted in Paper Mario, Bowser kidnaps Peach because he is in love with her. It may also be because he wants to take over her kingdom, which was why he kidnapped her in the first game, but it seems to be more about love than power.
After the amount of times he has kidnapped her I assume not
There's never been any absolute proof of this. There are rumors floating around that she is the mother of Bowser's children, but there is no proof of this anywhere. Nintendo has made it pretty clear that she is in love with Mario, but nobody can really know for sure.