I was wondering why this game has never been brought to the west?
Sorry if this has been answered before…
licensing fees probably.
Ummm, because the first one wasn’t brought to the west (as far as I am aware)? Sarcasm aside, acquiring a license for a well known and beloved game, especially one that has had a successful anime adaptation, can cost quite a bit. Given that bishoujo games don’t exactly have the greatest sales in the west, it is likely that the investment needed to acquire such a license would not be recovered, let alone a profit made. I imagine that your best hope of a series like To Heart (or if you prefer, ToHeart) coming to the west is probably Mangagamer. I’ll leave it to someone else to explain why, since I’m so tired. (If I tried explaining, it would probably come out as gibberish.)
I’m not sure Leaf/Aquaplus is interested in investing the time and money to investigate the Western countries, considering their success and popularity in Japan.
So, the answer to your question is probably: “because the overseas galgame market sucks.”
They don’t need us. How sad! 
QFT.
Look at Konami. For decades they’ve maintained a steady foothold on the American game market. They’ve even assigned personnel in Japan, to dedicate themselves in making their games specifically for the US and European market (Castlevania and Silent Hill fall under this directive), because they sell better overseas.
Tokimeki Memorial? Not a chance in Hell.
Back in 2003, Konami had even made an official English page for the game. They let the domain name expire in 2007 (4 year lease), and it’s now held by one of those annoying resellers. God hates us.
That title, yea, but Atlus and to a lesser extent NIS and Marvelous have had more success with hyrbrid games that incorporate rpg or other gameplay elements with dating sims type elements.
To Heart 2 should be banned.
It includes Loli (girls possibly under 18), Assault (the male protagonist gets hit a lot), Girl (obviously), Student Council (as expected), (tw)Incest, and Slaves (sentient robots are considered personal property).
That’s at least six offenses right there. 
You forgot Brutality (Tamanee on her brother), Coercion (anything Maaryan-senpai makes Takaaki do), Binding (Karin is gagged and tied when becoming too curious about Ruu~ true nature…) and Confinement (…then is confined in the school sports equipment room).
That’s ten offences.