assert, affirm, allege, maintain, testify, claim

動詞 assert:

1. state categorically
   同義詞：asseverate, maintain
2. to declare or affirm solemnly and formally as true
   同義詞：affirm, verify, avow, aver, swan, swear
3. insist on having one's opinions and rights recognized
   同義詞：put forward
4. assert to be true
   同義詞：insist

1. We encouraged him to assert his view of the matter.
   我們鼓勵他堅持自己對此事的看法。
2. She asserted that he was innocent.
   她斷言，他是無罪的。

as.sert

v.tr.（及物動詞）
as.sert.ed,as.sert.ing,as.serts
To state or express positively; affirm:
斷言：肯定地說出或講出；斷言：
例句：
asserted his innocence.
他堅稱自己無罪

To defend or maintain (one`s rights, for example).
維護，堅持：維護或堅持（如，自己的權(quán)利）
To put (oneself) forward boldly or forcefully in an effort to make an opinion known, for example:
堅持己見：大膽地或強有力地提出（自己）的觀點，以使其為大家所知，如：
例句：
I had to assert myself in the meeting in order to ensure acquisition of the new book.
我在會上不得不堅持自己觀點以保證得到那本新書

來源：
Latin asserere assert-
拉丁語 asserere assert-
ad- [ad-]
ad- [前綴，表.朝，向.]
serere [to join] * see ser- 2
serere [參加] *參見 ser- 2

【引伸】
assert.able 或
assert.ible
adj.（形容詞）
assert.er 或
asser.tor
n.（名詞）
<參考詞匯><同義詞>assert,asseverate,declare,affirm,aver,avowThese verbs all mean to make a positive statement.Toassert is to state one`s opinion confidently but often without proof to support it:
這些動詞的意思是肯定地提出。assert 是指自信地講出自己的觀點，但常常是沒有證據(jù)來支持：
例句：
.I have endeavored to assert nothing but what I had good authority for. (William Sewel).
除了我確有把握的事情外，我不會斷然地講任何事情. （威廉·西維爾）。

Asseverate connotes sober sincerity of assertion:
Asseverate 指鄭重真誠的斷言：
例句：
.The taxpayer also asseverates that his return from Greece proves conclusively that his intentions were and are honorable. (Daily Report for Executives).
納稅人同時鄭重聲明他從希臘的返回，本身就非常有說服力地證明他的意圖，曾經(jīng)是，現(xiàn)在也是誠實的 （行政官員每日報告）。

Declare has the approximate force ofassert but may suggest formality of statement and authority in the speaker:
Declare 有接近于assert 所表述的力量，但含有表示講話者禮節(jié)和權(quán)威的意思：
例句：
Congress declared that it would reduce the budget deficit.
國會宣布將要減少預算赤字。

Affirm and aver stress the speaker`s confidence in the validity of the statement:
Affirm
Scientists cannot affirm the existence of life on other planets. She averred that solitude was necessary for creative work.
aver 強調(diào)講話人對所講東西正確性的自信：
例句：
科學家們還不能證實在其它星球上有生命存在。她斷言離群索居對于創(chuàng)造性的工作是必不可少的。

Avow implies frank and open acknowledgment or admission:
Avow 含有坦誠的，坦率的承認或確認：
例句：
.thinks the book succeeds in achieving its avowed purpose: to explain how the Court`s current role evolved through history. (Tony Mauro).
.認為該書成功地達到了公開宣布的目的：解釋當今法庭作用的歷史發(fā)展. （托尼·莫羅）。