Affirm and Co-sign

Affirm verb - To state as a fact usually forcefully.

Co-sign and affirm are semantically related In some cases you can replace phrase "Co-sign" with "Affirm", this terms are similar.

Co-sign verb - Sign jointly.

Affirm and co-sign are semantically related in pledge topic. Sometimes you can use "Affirm" instead a verb phrase "Co-sign", if it concerns topics such as give assurance.