The verb ‘assert’ is C1 in the English Vocabulary Profile:
[T] FORMAL to say that something is certainly true
‘assert yourself’ is C2:
to behave or speak in a strong, confident way
For example:
or
‘assert your authority/control/independence, etc.’ is also C2:
to do something to show other people that you have power
For example:
We need to assert our authority, increase security in Moscow.
An iWeb search for:
ASSERT _APPGE
1 ASSERT THEIR 3134
2 ASSERT HIS 1364
3 ASSERT ITS 1151
4 ASSERTING THEIR 1020
5 ASSERT YOUR 1002
6 ASSERTED HIS 670
7 ASSERTING HIS 659
8 ASSERTED THEIR 613
9 ASSERT OUR 484
10 ASSERTS HIS 460
ASSERT _PPX
1 ASSERT THEMSELVES 1288
2 ASSERT ITSELF 969
3 ASSERT HIMSELF 689
4 ASSERT YOURSELF 684
5 ASSERTS ITSELF 625
6 ASSERTED ITSELF 455
7 ASSERTING ITSELF 366
8 ASSERTING THEMSELVES 321
9 ASSERTED HIMSELF 274
10 ASSERTED THEMSELVES 265
A NOW corpus collocate search for:
assert their
1 RIGHTS 992
2 DOMINANCE 454
3 RIGHT 433
4 AUTHORITY 334
5 IDENTITY 207
6 OWN 197
7 POWER 191
8 INDEPENDENCE 190
9 WOMEN 132
10 TRYING 118
assert themselves
1 BEGAN 128
2 WOMEN 87
3 STRUGGLED 63
4 ABLE 51
5 TRYING 41
6 STARTED 41
7 BEGINNING 34
8 LEADERS 31
9 BEGIN 25
10 FAILED 25