The term lien means a burden or a charge while a bonus means an advantage or a reward. The proverb “There are no burdens without bonuses” illustrates a situation where the effort put into doing something will result in some kind of reward.
For example, when a company sets sales targets for a period, it often stipulates a bonus that the salesperson will receive if they reach the target. This works as a stimulus for the salesperson to perform better. In this case, the onus is the extra commitment that the seller is expected to make.
Onus
Burden is a term with predominant use in the legal field. For example, a certificate of real liens is a document issued by the Real Estate Registry Office, which shows the acts performed by the owner of the property. Indicates whether or not there is any encumbrance, that is, any mortgage, lien, etc., on the property. In Law, the burden of proof is the obligation of those who claim a given fact to have to present evidence for that fact.
Bonus
Bonus is a term often used as a way to attract consumers to purchase a certain product. Some examples of bonuses can be: telecommunications companies, supermarkets, bank cards, etc., which usually offer bonuses to customers who subscribe to certain types of services; computer games offer bonuses to those who manage to complete the various stages of a game; certain reprints of musical works sometimes add bonus tracks.