Motives

Prov 14:12
There is a way that seems right to a man,
but in the end it leads to death. 

16:2 All a man's ways seem innocent to him,
but motives are weighed by the LORD.

21:2

I want to exhort you on the desire to have a pur motive before God, to want to do right by Him. I think that's wonderful, and a good desire to have, and that God is pleased by it. I remembered Hebrews 3:12

For the word of God is living and active, sharper than any double edged sword, it penetrates even to dividing soul and spirit, joints and marrow; it judges the thoughts and attitudes of the heart.

I think discernment and purity is important, because we can be right intentioned but not 100% pure, etc. But we will get to more purity, etc., not as we search/focus internally (though sometimes necessary) but more as we meditate on God's Word.

Because it is the Word of God that divides soul/spirit, judges our attitudes, not our limited understanding.

I remember Abimelech and Abraham and Sarah, how God kept Abimelech from sinning because he didn't know that he would be sinning in Genesis.

Paul saying, because he persecuted churches in ignorance (as opposed to purposely)
and in the Law of Moses, people had to give sacrifices even if they sinned w/o knowing and only later realized it (Repent). 

So God looks at our hearts, and good intentions are good starts, and God will lead us to be purified. Because intentions are a good start but not everything. So ask for it (PSalm 139):
Search me O God
Know my heart
Test me and know my anxious thoughts
See if there is any offensive way in me
Lead me in way everlasting

It is God who searches our hearts (sometimes also us, in another psalm) but if you pray this, God will hear.
Ask that he gives you pure heart, clean hands (Psalm 24) and you will receive.

Psalm 19 - But who can discern their own errors?

    Forgive my hidden faults.

Keep your servant also from willful sins;

    may they not rule over me.

Then I will be blameless,

    innocent of great transgression

May the words of my mouth and meditation of my heart be pleasing to you

As we draw closer to God and he purifies us, things we thought were OK will be revealed to be sin. And that's OK. He will take you step by step as you seek him, ask for it, and let him. 2 Tim 2

Again, I want to commend you for your desire to have pure motives. I think that's a noble, good desire from God. I think that's heart that David had (Psalm 19), the man who was after God's own heart (I think maybe that means he sought after what God wanted, though he wasn't fully aware, he wanted to know) -- the man of whom God said, he will do everything I want him to do. (What praise! I want that from God!)

Be as innocent as doves -- heart intention
wise as serpents 

As we filter water, first we filter out the big stuff. Then the smaller. Then the particles.
The filters change along the way, and they may not be the same filters God is using on somebody else. But it is God who provides the filter. (I think Word of God is also a filter, so we can discern right from wrong.)

But I don't think we need to worry about or fear to a point of being paralyzed, doing wrong or making a mistake. We need to not go to rebellion -- deliberate, continued disobedience (knowing something is wrong) but God doesn't get angry at weaknesses or mistakes. God gives grace to the humble and his power is made perfect in weakness. When are are wanting to get better, seek it, and ask for his help, he is delighted! He wants to help you! He knows where you're at and what you need. Let him lead you. Seek his will in the Word and prayer. It is God who works in you to will and work for his good purpose.