Reciprocate (verb)

1. To respond to a gesture or action with a gesture or action of similar value.
2. To return or exchange something, such as a favor or a kindness.

Origin:

From the latin word reciprocatus, from reciprocare ("to move back and forth"), from re- ("back") + reciprocus ("moving back and fort.h")

Examples:

1. He reciprocated her love.
2. She reciprocated his kindness.
3. He reciprocated her gift with a gift of his own.
4. She reciprocated his invitation with an invitation of her own.
5. He reciprocated her help with help of his own.