Use 'gladden' to express a deep, heartfelt happiness rather than a superficial joy.

Emotional Impact

'Gladden' often implies that happiness is given or spread to someone else.

Positive Effect

It's used when the happiness relates to a sense of deep satisfaction or pleasure.

Use 'gladden' to describe a personal surge of happiness, often from within.

'Gladden' can indicate a response to something specific, like an event or sight.

Though not as formal as other words, 'gladden' carries an eloquent touch in modern contexts.