It can be caused by either excessive tear production, insufficient tear drainage, or a combination of both. Epiphora can be acute or chronic, most likely everyone has experienced at some point the tearing and irritation that results whenever something gets into our eyes.
Assertive is defined as someone who is self-confident and strong willed, though sometimes domineering or pushy. An example of someone who may be assertive is a car salesman. The definition of assertive is something with a strong taste or smell. An example of a something with an assertive smell is an aged blue cheese.
To assert is defined as  to make a statement with full confidence of its truth and factuality. An example of a person who may assert something is a scientist who is very confident in his supporting data. The definition of assert is to make a claim or defense. An example of someone who may assert is a defense attorney who believes strongly in his client's innocence. To assert yourself means to make your beliefs or desires known in a strong and forceful way.