The Hawk and the arrow

Clint Barton a.k.a the Hawk/Hawkeye, is a master assassin and a well respected member of shield whose weapon is simply a bow and arrow.
Natasha Romanoff(Natalia Rushman/Natalia Alinova Romanova)
a.k.a the Black Widow is a master Assassin who works for no one and has a very specific skill set,former member of KGB and red room,
They would never let anyone get in the way of succeeding the there missions however when Clint is given the mission to kill the black widow everything changes and he makes a different call when they both form a unique friendship/partnership and fall madly in love.
"This was something they never trained for."
"love is for children"
"He made a different call....."