I heard that it is Haraam to highly praise a person to his face. But can a husband flatter his wife so that the love is increased?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

First of all, you should know that in principle it is permissible to praise people, and the scholars have put some conditions for this, among which is not to lie or exaggerate in praising.

As for the husband, it is permissible for him to exaggerate in praising his wife because among the objectives of the Sharee'ah are the stability and continuation of the marital life and the continuation of affection between both spouses with the purpose of winning the wife's love by showing one's love to her.

The husband may use general expressions in this respect.

Finally, it should be noted that exaggerating in praising and praising too much, may lead to results contrary to what was intended.

Allaah Knows best.