I want to come closer to god, and he said don't confess by mouth but by heart, how do I do this

I also struggle with coming closer to god but this is what i think this means. you need to come to terms with your sins instead of confessing them. you then need to make improvements in your life to make yourself a better person. this change of heart shows god you are trying your hardest and that you have became a better person. hope this helps and good luck!