词根：sever = earnest, 表示“诚恳”

severe a. 严肃的；严厉的

persevere v. 坚持不懈（per始终+severe→始终诚恳→坚持不懈）

asseverate v. 正中申明，断言（as一再+sever+ate→一再诚恳表示→郑重申明）

词根：sever = serious

  来源于拉丁语的sever 意为 serious,earnest,to cut。

同源词：

1. asseverate（使变得非常深刻和严肃 as<ad(=to,intensive) + sever(=serious)）
  vt.断言
  asseveration n.断言
  The professor asseverated that more than half the students had cheated. 教授断言一半以上的学生都作弊了。

2. persevere（从头到尾始终非常严肃 per(through,throughout) + sever(=serious)）
  vi. in + sth 坚持不解；（辩论中）固执已见
  perseverance n.忍耐，坚持
  persevering adj.有毅力的,锲而不舍的；固执的
  It's important to persevere,especially when you feel like quitting. 坚持不解很重要，尤其是当你想放弃的时候。

3. severe
  adj.严重的；剧烈的；严格的，苛刻的 *sever(=serious)

4. dissever
  v.（使）分离；（使）分裂 *dis(=away),sever(=cut)

5. sever
  v.切断，割断；中断；断绝；（使）分隔，（使）分离 *sever (=cut)

6. severance
  n.割断，断绝；分离，隔离 *sever(=cut)
  severance payment 解雇金，离职金
  severance of diplomatic relations/of communications 断绝外交关系/通信中断