The difference between Approval and Assent

When used as nouns, approval means an expression granting permission, whereas assent means agreement.

Assent is also verb with the meaning: to agree.

check bellow for the other definitions of Approval and Assent

Approval as a noun:

An expression granting permission; an indication of agreement with a proposal; an acknowledgement that a person, thing or event meets requirements.

Examples:

"I need to get an approval on this purchase order."
Approval as a noun:

An expression of favorable acceptance and encouragement; a compliment that also condones.

Examples:

"Words of approval never seem to come from him."
Approval as a noun (especially, philately):

Something mailed by a seller to a collector to match his stated interests; he can approve of or return the item.

Assent as a noun:

agreement; act of agreeing

Examples:

"I will give this act my assent."