The heart of her husband trusts in her, and he will have no lack of gain.
When someone or something is trusted, a certain release of control is delegated to the thing or person trusted. “I trust a chair,” means that I intend to give up supporting myself by my legs, and delegate that effort to the legs of the chair. If I trust my wife it means I find her able to take over the areas I delegate to her, and in those areas, since I hope to gain from life, I will gain in her efforts. It is the center (“heart”, as in heart of the tree) of the husband that relinquishes control of areas of their life together. A “Goodwife” is not one who makes her husband concerned or suspicious of her abilities. No one likes to be in the chair that gives cause for suspicion. To avoid embarrassment, you start to tuck your legs under you, in case the chair fails. What then is the point of the chair?