ils

1. they (male or mixed group)
2. (informal) they (female)

signent

third-person plural present indicative/subjunctive of signer

ensuite

in turn, subsequently, thereafter, then

leur

• Pron

  (to) them

• Det

serment

oath, pledge

soumettent

third-person plural present indicative/subjunctive of soumettre

au

Contraction of à le (“to the, for the, at the”).

de

• Prep

  1. of (expresses belonging)
  2. of (used to express property or association)
  3. from (used to indicate origin)
  4. of (indicates an amount)
  5. used attributively, often translated into English as a compound word
  6. from (used to indicate the start of a time or range)
  7. used after certain verbs before an infinitive, often translated into English as a gerund or an infinitive
  8. by (indicates the amount of change)

• Article
• Noun