From Peter Pett's commentary on Prov 11.30:
‘The fruit of the righteous is a tree of life,
And he who is wise captures hearts (nephesh -the breath, the inner man).’
The crowning blessing of the righteous is that they become a blessing to others. Their fruit is a tree of life, a lifegiving tree. By their lives, the ‘natural’ product of their walking in wisdom with God, they are a source of life and wellbeing to others. Through their wisely lived lives they win the hearts of men. We translate ‘hearts’ because that gives the sense. It does not strictly mean ‘winning souls’ in an evangelistic sense, although that is undoubtedly one of its outcomes. If we would ‘win men’s souls’ we must first win men’s hearts. Nephesh indicates the inner man, the ‘breath of life’. Jesus may well have been taking up this thought when He said to His disciples, ‘from now on you will catch men’ (Luke 5:10).
The reference to the tree of life indicates that God’s purpose for the spiritually wise, who follow God’s wisdom, is that they will play their part in restoring what has been lost by the fall. And they do it by attracting others to God’s way of wisdom. It is part of the process of restoration. We too are to be a tree of life to men and women as we attract men to Christ by the beauty of our lives, and of course by proclaiming His wisdom.