I am sorry to stand in your way.
迷惑かけてごめんね。
Please pardon me interrupting you.
困らせてごめんね。
I am sorry it's confusing.
I am sorry to make such a claim on your friendship―presume so far on your friendship.
うるさくてごめん
I'm sorry that I disappointed you.
I'm so sorry I frightened you.
I must apologize.
申し訳ないこと
I am sorry for the trouble we may cause you.