This word has at least two different meanings.

talaga, adv
really, truly, indeed

Mahal kita talaga.
I truly love you.

Talagang talaga.
Really, truly. So much!

Talagang ganyan.
It’s really like that.

Talagang ganyan ang buhay.
Life is really like that.

A similar Tagalog word is totoo (true).

There is also another, unrelated meaning for the Tagalog word talagá, accented differently. It is usually in conjugated form.

Nakatalaga sa tadhana.
Destined by fate. 
(Written in the stars.)

A similar-looking but unrelated Tagalog word is dalaga.