Half-hearted practice of Dhamma results in chaotic misunderstanding. Whole-heartedness may have at its core devotion, and a mind which goes beyond everyday thoughts and activities. Another facet which goes together with mindfulness, is clear comprehension. Mindfulness is knowing only, without any discriminating faculty. Mindfulness does not evaluate or judge, but pays full attention.
Clear comprehension has four aspects to it.
Thought, speech and action are our three doors. The thought process needs our primary attention, because speech and action will follow from it. Sometimes people think that the end justifies the means. Both means and end have to be within the Dhamma. The fourth step is to check whether our purpose has been accomplished, and if not, why not.