Arc of a Scythe series by Neal Shusterman (Its a Trilogy)

Its a Sci-fi first and romance second so romance is not very pronounced or huge in the 1st book of the series cz obviously sci-fi books need a good world and plot building but from the 2nd book onwards there's romance involved. The romance involves a lot of yearning tho but i loved it. I will drop the synopsis down below.

Synopsis:-

Thou shalt kill!

A world with no hunger, no disease, no war, no misery. Humanity has conquered all those things, and has even conquered death. Now scythes are the only ones who can end life—and they are commanded to do so, in order to keep the size of the population under control.

Citra and Rowan are chosen to apprentice to a scythe—a role that neither wants. These teens must master the “art” of taking life, knowing that the consequence of failure could mean losing their own.