Learn Dutch: Wij hebben veel geïnvesteerd. Het resultaat is echter slecht. - We have invested a lot. The result, however, is bad.

In English, we often start a sentence with "However, ...". In Dutch, echter usually comes after the conjugated verb (here, is). You can sometimes put echter at the very beginning, but it forces an inversion (Echter is het resultaat...) and sounds quite formal or old-fashioned in modern Dutch.

Could I use integendeel instead of echter in this sentence?

No, integendeel means "on the contrary" and is used to completely reject a previous statement, usually a negative one (for example, "The result isn't good. On the contrary, it's terrible!"). Here, you aren't rejecting the fact that you invested a lot; you are just introducing a contrasting disappointment. For a simple "however", echter is the right choice.

What about daarentegen? Would that work instead of echter?

Daarentegen translates to "on the other hand". It is best suited for comparing two contrasting subjects or situations, like "We invested a lot. Our competitors, daarentegen, invested nothing." Because this sentence just describes the disappointing outcome of your own action, echter sounds much more natural.

Why does geïnvesteerd have two dots on the letter 'i'?