Yes, Pinterest is  safe to use:

• Because users must sign in and password protect their accounts, Pinterest is as safe to use as most other social media sites. It also doesn't ask for any personal or financial information, so there's not much to lose by signing up. Spam or frauds from other users are your main concerns.
• One of the primary security concerns is that, despite the fact that you must enter your full name and age in order to join up, Pinterest lacks the ability to verify that the information you provide is accurate. This means that, while the majority of people use the site honestly, some people use the anonymity of the site to hide their identities.
• With bogus pins promoting freebies or contests, these people sometimes try to deceive others into disclosing personal information. Others will purposefully ruin other people's accounts by inviting them to cooperate on boards and then intentionally flooding those boards with undesirable stuff.

Read More: How is Pinterest better than Instagram?