It’s not nefarious.
She acts girly around him. He has an effect on her...or maybe she is the honeypot. Don’t know..but you don’t seem the same girly girl reactions around other leaders.
She skipped her Dad’s rally for this event...which is a UN extravaganza throwing shade at the US.
She has a very outgoing and welcoming personality in general. Not just towards him. Also, I believe his wife was there along with others from DC.. it was appropriate for a representative from the first family to be on board. I believe Ivanka and the Trudeaus are also about the same age so of course there would be some common ground/comfortablity there, as well. Not everything has sexual overtones. They are social individuals/adults not highschool kids.