The phrase "assertive enough to be" is correct and usable in written English.
You can use it when discussing someone's confidence or decisiveness in a particular context or situation.
Example: "In negotiations, it's important to be assertive enough to be taken seriously by your counterparts."
Alternatives: "confident enough to be" or "decisive enough to be".
The trick to acing these interviews is to be able to be assertive enough to still give your interviewers a sense of who you are while also showing that you're considerate toward others and can work well in teams.
Obviously, you want people to be assertive enough to leap forward, but you also want them to be self-aware enough to honestly evaluate themselves.
Those sailors did not need a shoeshine, but the fact that a young boy would be assertive enough to pursue the opportunity must have been impressive because they kept me busy.
For example, merging lanes in fast-moving traffic requires a driver to be both assertive enough to complete the maneuver without causing others to brake and smooth enough to feel pleasant to our passengers".
They are also looking for a person who is assertive enough to speak loudly and lead a group through a potentially crowded museum.
Vendors and cab drivers will think that they can overcharge us because we won't be assertive enough to negotiate a better deal or informed enough to know the situation.
Of course, this doesn't mean you need to sit there in pain if he actually hurts you––be assertive enough to point out that it hurt!
By 2009, Fisher was assertive enough to support locked-out referees, saying that "anything less" than the best officials "is unacceptable to our union".
A wedding? My manager thought I'd be perfect in this costume, meaning that I was not assertive enough to decline the opportunity every sixteen-year-old girl dreams of: going out in public dressed as a formal dairy product.
