Telling it “like it is” and being nice are not mutually exclusive. I see honesty and kindness as two very important values and both essential to healthy relationships. I often see people chose between the two as in “It’s the truth” (and therefore okay that the comment is hurtful) or “I didn’t want to hurt his/ her feelings” (and so didn’t say anything or didn’t speak the whole truth). Of course it can be challenging at times to find a way to do both. Start with focusing on the conversations or times when it is especially important to you to communicate your truth in a respectful or kind way. Try writing down what it is you want to say. Let it sit for a while (an hour or a couple of days). Then go back to it to look at how you can say this kindly. One way to do this is to think about being on the receiving end of the message. This can help eliminate some unnecessary jabs.
Communicating honestly and with respect for others allows you to communicate effectively. People are more likely to hear what you have to say when you integrate these qualities into your conversations with them.