has been guaranteeing

• present perfect progressive

  present perfect progressive

  Used to describe an action that began in the past, has continued continuously, and is still in progress.

  of guarantee (3rd person singular).
  guarantee

  noun

  a promise or assurance, especially one in writing, that something is of specified quality, content, benefit, etc., or that it will perform satisfactorily for a given length of time.

Related Words

• agreement
• assurance
• certificate
• collateral
• contract
• deposit
• insurance
• security
• warranty