I'll start with a quick elaboration in case you might not be familiar with these terms from the Christian or Jewish perspective.
Sowing is the term for when we talk and share our faith with others, we share the gospel and nothing really changes for the person. Like planting a seed in your backyard for tomato plants to grow weeks later we share our faith and then the person goes home and start to think on their own. To make up their own mind.
Reaping is the term for when you are the person who helps someone come to accept Jesus. You are there when they make that honest, freewill decision.
The hard part is that sometimes we desperately want to reap, we want to see a person come to life change! But we are only the sower for this person.
Often times if you speak into someone's life and plant that seed. They will continue to make bad decisions for a time. Or a lifetime... But that seed, if planted, can grow into harvest later on. That someone else might reap.
Now for the twist...
Taking responsibility for other people's outcomes is kinda like sowing and then expecting that we also are there to reap! It's a frustrating place to be honestly. Because it's driven by good motives! You want that person to have a life change! But the reality is that most times it's not gonna happen that way.
So the question is
Are you a sower? Are you a reaper?
Embrace your calling regardless of which you are.
Don't let your care and concern for that person let you get frustrated when you aren't both!