Romans 10:17 — "faith cometh by hearing, and hearing by the word of God" — places the source of faith outside human persuasion ability. You cannot produce faith in another person. You can speak, you can live with integrity, you can pray. But faith, when it comes, comes by hearing the word, not by the quality of the human presentation. The rejection of your faith by someone you love is not evidence that you presented it poorly. It is a statement about the condition of the soil, which you do not control.
1 Corinthians 3:6–7 draws the division of labor precisely: "I have planted, Apollos watered; but God gave the increase. So then neither is he that planteth any thing, neither he that watereth; but God that giveth the increase." The conversion of another person is God's work, not yours. The rejection of what you have shared is not a verdict on your faithfulness. The planting and watering are your assignment. The increase is not.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.