Every character on Jiǎoluò Shūwū read as xin in any tone — 3 readings total across the four tones. Pick the tone you mean.
If you have the sound xin but not the character, here are the 3 characters read this way: 心 (xīn, heart, mind), 新 (xīn, new; fresh; recently; novel), 信 (xìn, trust, faith, credibility). They split across 2 tones, so the tone is what separates them.