it's 高兴 not 高心... 很高兴认识你 can't be abbreviated to 认识你 if you are saying thanks to someone's help, you should add 了：麻烦你了。 if you are asking for someone's help, you can say：麻烦你帮我...行吗？

nice to meet you: 很高兴认识你（hen3 gao1 xing4 ren4 shi0 ni3, 0 means there's no tone） sorry for troubling you: 不好意思麻烦你了/打扰了。

加我吧，i can help you！

Nice to meet you 很高兴见到你（for the first time:很高兴认识你） hěn gāoxìng jiàndào nǐ（hěn gāoxìng rènshi nǐ） "Sorry for troubling you" 不好意思，麻烦你（您）了 bùhǎoyìsi,máfan nǐ（nín） le 抱歉，打扰你（您）了 bàoqiàn,dǎrǎo nǐ（nín） le P.S: 1. "抱歉"，"不好意思":they are the same meaning here. they can have a change which each other. 2. "打扰(dǎrǎo)":you see the to character are both in falling-rising tone（the tones in Chinese：阴平，阳平，上声，去声。the third tone：shàngshēng）.When two falling-rising characters meets, the first one should pronounced rising tone. "打扰(dǎrǎo)"→ "打扰(dárǎo)" 3.”您" is the respectfully address for “你” Eric‘s answers are right. I just put them in order~ :P

不(bù)好(hǎo)意(yì)思(si)麻(má)烦(fan)你(nǐ)了(le) 打(dǎ)扰(rǎo)了(le)