Answer by Japanese teacher
Online dictionary is useful for a quick translation to grasp the meaning but the translation rendered may not be culturally or socially acceptable.
“Tanoshimi ni shiteimasu” (looking forward to something) is appropriate if you are talking to a friend or writing a personal letter but not so for business.
For business, you can use the suggested expressions instead.
In the first expression, both “ohenji” or “gohenji” (your reply) are acceptable. Traditionally, people use “gohenji” but recently, more people are using “ohenji” instead.
The second expression uses “omachishite orimasu” (waiting) which is a more polite (or humble) version of “omachishite imasu”.
If you are more junior than your colleague, you can consider the second expression instead because it is good to humble yourself in front of a more senior colleague.