Bridge: Strong balanced hand rebid?
Assuming a relatively standard framework, then partner's response shows 6-9 points with no 4-card Major and an inability to make a weak raise in diamonds. It is generally desired to play in a 3NT game with two balanced hands when the partnership assets total 25 (or a good-matching and equally divided 24) points. Partner's announced 6 with your 19 make 25, so the book bid is a direct raise to 3NT, as stated by ruds.

However, there are strategic considerations. There may be difficulties with so few partnership assets hidden. The opponents may well be playing double dummy from trick 2 or 3 on if a good lead is found. I would tend to underbid by a point here, and raise just to 2NT with exactly 19, when not vulnerable. It is winning bridge to stretch slightly (to game, not slam) when vulnerable, and retract slightly (again wrt to game only - small-slam bidding is reversed) when not vulnerable. This reflects the unequal rewards and benefits of vulnerable and not vulnerable game (or rubber) bonuses.

The raise to just 2NT invites partner to continue on with 8-9 points, and to pass (or correct, if your agreements allow) with just 6-7. 



Daily smile for those who know Latin: I saw the use of boni in place of bonuses last weekend in an answer on another site - clearly by someone who didn't know that boni means "good men", and Boni means specifically "the good men who conspired to assassinate Caesar". The meaning of the answer changed dramatically with that interpretation.