Two of my favorite female TV assassins are:

Villanelle in Killing Eve
Alice Morgan in Luther

For their own reasons, they discover that Bruce Wayne is Batman and want to assassinate him. They reasonably decide that taking him on as Bats is not a good idea. So they want to come after him when he is Bruce. Let's say at some charity affair, where he is wandering around and eating the shrimp, salmon and chopped liver.

They can have a reasonable amount of time to build a persona and attend the affair as a charity rich person, a staff member - anyone who would reasonably be at such a party. No super weapons, just the things they have used in the shows. They can work together if they think that will be a good plan.