Help
This is from bridgewinners once more. Obviously 3NT is too low, so what went wrong. First of all you need to have a plan. The hands are very basic, so I will not go into details.
South should realize that there are no issues to show her suits. If north bids spades, are you not already thinking how can 4♠ not make. South has a massive fit for spades, very good for clubs and something for diamonds. South has a super-max-min-no-fit versus hearts, so you accept invites in a flash, but is it going to be 3NT or 4♥. If south has GF with hearts, things became tricky, because you dont have a fit, but good controls and a good side suit.
North's plan is very simple: 19bal vs 12-14bal or 11-12unbal is not enough to force 6NT. So north has to explore what south has. If south has one-, two- or three-suiter, you have support. Let south tell the story, if there is any.
The bidding was completely standard up to 2♥. 3♣ is not right, unless it is exactly what their system says. Support diamonds! What if partner has one suited in diamonds: you just found a great fit, partner is often strong without heart wastage. If partner has red suits, you showed support, while showing hearts are likely leaking in 3NT. North could have three suits: something like 3451, 1453, or even 1444. You better raise diamonds again. You can be in a 4-3 fit, but partner is going to try 3NT or try to retreat to clubs maybe. What if 3♦ is not forcing? That is a system problem, I cant help with that. All I can say support diamonds one way or another. Just think about hands partner can have, when she introduces diamonds like we have here. What if partner is balanced? It is not a problem to raise diamonds, when you are suggesting exactly what you have and more. If partner can't cope with 3NT, the better it is that you showed support.