A punishable sin will cause sadness and depression to the soul of the believer. The believer who sincerely loves Allah (swt) is angered and depressed by the sin he has committed. Feelings of sadness begin to roam the mind, and the believer will lose confidence many times. Feelings of doubt are evoked in the sense that the believer feels that Allah (swt) may not support him at a certain point in time as punishment for what he has rendered. This doubt is not in the sense that he feels Allah (swt) is not merciful enough to forgive him; rather, it is the doubt about what will happen if Allah ever decides to retaliate for what he has done.
Praise's be to Almighty that he didn't created odor for sins . If sins were to have any odor then none of you would be able to sit beside me ~ A strange stranger.