In reference to Proverbs 4:23, which talks about "guarding your heart"…Is this is about dealing with issues of dating and romantic relationships? Or is it just a warning to watch what flows from your mouth, eg. curse words?
While we cannot offer specific relationship counseling or advice, we can offer a perspective on Proverbs 4:23. That verse appears in a larger context of teaching which we must consider:
The passage commands the believer to remain fixed on living in good, godly ways. Specifically, we should put away lies and deceptions, preventing our eyes from leading us into sin and watching the path of our feet (i.e., the choices we make in our daily lives) to ensure we follow the Lord's commands diligently. Collectively, these behaviors are called "watching over our heart" (v.23).
So this passage is not intended as relationship advice, per se. The passage is speaking about much more important issues: living a life of godliness and obedience to Christ, which has eternal ramifications for the believer.