My experience comes from LARPing in Russian Federation only, almost exclusively in Moscow. I have never LARPed in another country, and my experience outside of Moscow is very limited.
LARP doesn't change much about touching
Usually, unless the rules clearly permit this, just as in any other situation, you should probably refrain from touching another player unless they explicitly agree, verbally or non-verbally. For example, hitting somebody from behind to slay their character (in accordance with the combat rules) is okay, groping them from behind (unless the rules specifically say that it's allowed) is not OK. LARP or not LARP, this does not change.
As long as you only use words, anything is generally OK, even verbal abuse that targets characters (as opposed to targeting players). If the other person is not okay with what you are trying to do, they can stop it in-character. They can refuse verbally, they can call the guards if it's in a town, they can use in-game physical violence.
Watch the other player's reactions
If they are really not comfortable with what you are doing, it's often a good idea to stop. For example, this summer I played a constantly drunk wizard apprentice who tried to (unsuccessfully) flirt with every woman he could see. When someone clearly wasn't OK with this kind of role-play (e.g. didn't respond to it, showed a disgusted face, stepped away quickly), my character (me) disengaged. In-character, it meant some more alcohol kicking in and my character falling unconscious. OOC, I was completely sober and just letting the other person escape the situation.
Anyway, in my area, unless you cross some boundaries like physically assaulting the player, if the other player is not comfortable with your role-play, it's considered their problem. Especially if you are doing something directly permitted by the rules.
Your mileage concerning long-term consequences may vary
An interesting remark: different players may have different expectations about the real-life consequences of such role-play. Most (myself included) presume that once the game stops, all relationships between characters vanish. Others think that if they started an in-game romance, it ought to continue in real life.
If something is really hurting you as a player, disengage
If a scene is really uncomfortable for you, it's better to slightly discomfort everyone around you and break character than to get a psychological trauma. If they don't stop, disengage, contact a game master and state that you are leaving the play. Your character is likely to be announced dead, but you will avoid a far less pleasant experience.
Again, my answer is only based on my experience, and only in Russia
If you are joining a new community, it's better to ask some of its members on the subject: as you might have noticed in my wall of text, even in the same country you can see very different approaches to the subject. Also, notice the plural form: ask more than one person, preferably way more than one. Their opinions may vary greatly.
Your mileage may vary even if when you play in a Russiant city different from Moscow, and Moscow itself is big enough to have very contrasted communities. Me saying that something is OK doesn't mean that it will necessarily be 10-4 where you play,